Many University Philosophy Departments have sections entitled "Why Study Philosophy?" Most of them cover the same basic points, and you'll soon get a feel for the main reasons. Below I link to a few examples of such sections; some of them are slanted more towards career prospects, others more towards personal development. The U.S. ones in particular are often rather regionally specific with regard to education and employment details. To find more sites, just enter "why study philosophy?" into any search engine (how do you think I found the ones below?).
My own advice would be that you should study philosophy if you enjoy it; indeed, that's the best reason for studying anything — and if that means the closure of Management and Economics departments, so be it. The idea that any seventeen- or eighteen-year old should choose to spend three or more years studying something she doesn't enjoy in order to get a well-paid but even more tedious job is depressing (not to say slightly chilling).
For this section I take my example from Judaism's attitude to religious conversion. The Rabbi involved must make three genuine attempts to dissuade a would-be convert before she is allowed to become a Jew. That seems to me to be an excellent condition, and one that I shall here apply to those who intend to go into philosophy as a career. (Actually, what I say here applies to many if not most areas of academia.)
As you'll see, therefore, this isn't a negative version of the previous section, whose links lead to sites concerned to give reasons for studying philosophy rather than for becoming professional a philosopher. I can't think of any reason not to study philosophy.
Let me start by giving a few genuine but anonymised examples of experiences of people trying to make it as philosophers. The examples are all from England (if anyone reading this has similar examples from elsewhere, send them and I might add them).
Example One: "John"
John was working on a casual basis for a University philosophy department, who seemed perfectly happy with his teaching. Everyone was very friendly and supportive, and he began to feel at home. Of course, he was being exploited to the hilt, as everyone is in such situations, but he could tell himself that that was the fault of nasty management, not the academics.
Then a temporary position came up -- only a year, but full time; paid vacations, a decent income, some security, however slight. He was encouraged to apply, and did. He didn't expect to get the job (there were other people in his or similar positions), but there was at least a chance. The deadline for short-listing approached and passed, and no word. It soon became clear that he hadn't been short-listed. It had to "become clear", because no-one told him. Ever. Rejection by silence.
Well, perhaps he'd been wrong about his teaching -- perhaps the department weren't happy with his work, but hadn't said anything. Then he was asked to teach again the following year. That's right; good enough to teach but not even to be short-listed for a temporary position.
But the point of this story isn't the unfairness, the peculiar light that it sheds on the rationality and morality of hiring procedures. No, the point is that he smiled (albeit wanly), and accepted the teaching. People in his position sooner or later lose most if not all of their self respect.
Example Two: "Jane"
Jane had taught for a College for some seven years on various short-term contracts. Despite some peculiarities of her treatment there (Colleges generally like to make sure that temporary teachers are fully aware of their lowly and precarious positions -- otherwise they might get uppity, might keep some self-respect), she'd been happy. The College was more than happy with her work, which had been dedicated and much appreciated by those she taught.
Then, in her seventh year, she was told that her contract wouldn't be renewed. It was College policy not to keep temporary lecturers on for too long. Well, not universally-applied policy, because there were plenty of counter-examples, but policy anyway. No embarrassment or sign of regret, no recognition of what was being done to another human being on anyone's part; just "thanks for the seven years of dedication, now go away."
Her students were upset, she was more than upset, her friends found it incomprehensible. I find it incomprehensible. Unlike the students and non-academic friends, though, I didn't find it surprising; far from it -- it's par for the course.
Her next College position went similarly, until after a few years she was offered a one-year renewal of her contract, and she asked if it would be possible to have a two-year contract (just to give her a little extra security about her future). Oh no, was the reply, because then she'd have worked for the College for five years, and would be legally entitled to a proper job. They offered her a year and nine months instead. She waited for the letter of confirmation and contract... and waited... and six months later she received an e-mail explaining that, because the College had just been allowed to appoint a permanent Fellow, they'd only be able to offer her one year after all.
The next stage repeats part of the last example. Jane was actively encouraged to apply for the Fellowship; she had the best student reports anyone had ever seen, her lectures were extremely popular, her work for the College had been excellent. Somewhat reluctantly (knowing what would happen) she applied. She wasn't even short-listed.
(This has happened to me, as well as to a number of friends and colleagues; encouraged, even approached by another University, to apply for a job, then not short-listed. What's going on exactly? None of us knows.
Example Three: "Joe"
Joe taught in an area of philosophy that was very popular with students, but which few philosophers in the University were able or willing to teach. He was therefore much in demand, and in term time was generally up to and often well over full-time teaching in that area alone. He had also given University lectures for three years - voluntary and unpaid - which were very popular and well received. However, he wasn't a member of the Philosophy Sub-Faculty, which meant that he wasn't allowed to use the library or other facilities. Indeed, he had an embarrassing experience when trying to use the library of a related faculty, very relevant to his teaching, and was turned away.
So, he wrote to the Sub-Faculty, explaining his position, and asking whether some arrangement could be made. Obviously he'd have liked some sort of real position, given the way that Colleges and the University were relying on him for a large proportion of their teaching, but he'd been around for long enough to know academia (if you can get it cheaply, why pay more?); he therefore asked if he could at least be made a member of the Sub-Faculty, and so be able to use the facilities that he needed for his teaching and research.
Of course you've guessed it. He was refused. It would "set a bad precedent". A pretty pathetic reason for a philosopher to give, but academics tend to be philosophers only when they're writing their books and articles; practical reason is switched off for their dealings with real life and other people.
In this case he retained some self respect, and he stopped giving his lectures (though this was cutting off his nose to spite his face, as he'd enjoyed them), but the need for survival meant that he couldn't stop teaching for the Colleges.
I'll leave it there for the moment; there are hundreds of stories like this, probably many of them even more dispiriting. Like Jane's more recent experience, in which she was rejected for a temporary job at a College for which she'd been teaching for three years, with excellent results and to general approbation. Why didn't she get the job? Because in the (rather bloated) interview process, she was subjected to aggressive questioning, was in any case nervous in interviews, and so performed hesitantly and unconfidently. "You can't have this teaching job because, although you can teach well, you're not good at interviews." It's a pity she wasn't applying for a job as an interviewee, then her teaching ability might have been a plus.
Of course, some people are lucky; they slip straight into a decent job, and never experience any of this. But the majority are in this position; their dedication to philosophy - in terms of both teaching and research - keeps them going, but they're slowly ground down. They're forced to teach far more than full-time hours in term, to teach summer schools or take on other work in vacations -- and when they apply for proper jobs, they're told that they haven't published enough. And, of course, they're told this by people who have paid vacations, who get sabbaticals... and who sometimes have few publications themselves.
Why am I still in it? My average income is about 4,000 pounds a year (yes, that's right, no mistake -- four thousand pounds; verified and provable, as it had to be when I was fighting for a reduction in my Council Tax), yet I teach as much as double full-time hours throughout the year, as well as some evening classes and Summer Schools. I teach in three Universities in three different cities, so spend a fair amount of my time travelling (for which I'm unpaid, of course).
Why am I still in it? I still enjoy teaching, and I think that I do it well. I enjoy philosophy, and I think that I do that well too. I gave up a well-paid job in order to spend a number of years studying and preparing for a life in philosophy, and I'm damned if I'm going to give up.
Still want to go into philosophy as a profession? If it's because you don't really believe me, then think again. If you believe me and still want to do it, then good luck; you'll need it, but your dedication to the subject probably means that you deserve it.