Agreeing with most of the above, and also to clarify, I'd correct 'absolutely no job prospects'. Besides specialised studies, there is teaching, academia, and one of the larger ones that people seem to forget, public service at state or federal level.
And I'll repeat that many people doing arts degrees realise that university isn't just about a dollar conversion to employment- it's a rounded experience and education is immensely valuable for its own sake. There is a reason why some places (see the University of Melbourne) run a generalist program before you can specialise into your 'career' area.
Whether you think that's a good idea or not, I'd hardly infer that people doing an Arts degree have made some sort of terrible decision in life.
Oh, and as an addendum: I think as an Arts graduate I have a higher chance of actually enjoying a job I will end up doing than if I had done, say, a commerce degree with good job prospects.
