What's the benefit of school and university knowledge if you don't get a decent job...

The first 10 jobs you get, and the next 10, are just pit stops along the road. Your education is permanent, and hopefully continually growing even after college. It will influence which jobs you find acceptable and which jobs you leave, and it will inform your path as you work towards better and better jobs. You don't get one degree and plug into one job -- and many directly job related things that you learn will only apply for a few years, as conditions on the ground change and change again. You education is you, not your job.