Cheating, working for the sake of grades alone, and extrinsic values is the only string which binds the system together already. The life line is already short- not that students ever attend schools for actual education anymore. At least a source of income might prevent some of the massive population of drop-outs from quitting altogether.
I think incentive to do well is okay, but yet, I don't think it should be necessary. I only voted "yes" because it worked for me when I was struggling in middle school. But, I don't think it should be a requirement by any means. That's completely up to the parents. It's not exactly an unrealistic concept, though. When you do well at work, you get rewarded with bonuses, pay raises, and extras.