It's not just about the money, or the job at the end. Why the absolute f*ck would you bother going to university if you didn't care about the subject in the first place!
If your subject is something you are passionate about then you'll work for it.
If you picked your subject just for the job at the end then you work for the best possible grade so you can get the best possible job.
If you don't care either way get the hell out of academia and get a 9-5.