Let's give one example, Alabama had a player who was formerly homeless. He was accused of taking impermissible benefits, for a set of bedroom furniture. Now, consider that for a bit...
Do most of these guys need the $5,000? No, not really, but also consider the fuss recently about what Braxton Miller did, which was post a picture of a product he was selling (kind of like Avon for athletes) which as it turns out was a violation since he was using his image to sell the product. There are actually a lot of jobs that athletes can't have, due to it being potential violations.
On top of that though, it's a matter of their time. They are expected to perform on the field as athletes, and this involved a grueling schedule and they are expected to perform academically, which is also a full time schedule. There's really not a whole lot of time left for work after that anyway.
I am in no way against the stipend, I think the standard should be more consistent, but the fact is it actually existed before the NCAA started trying to level the playing field and what not (to the point that having a cookout was a violation). It makes sense, it gives the athletes enough money to insure their needs are met, now some will still get in trouble, some will still do violations, but it might also go to buy some family a bed to...