If you only work hard enough to receive your salary then you can't ask for a raise. If there is surplus between how much value you generate and how much you are being paid that's an opportunity to switch employers and collect the surplus.
At many salaried companies, comp is banded and stepwise. There's a bar for you to reach that puts you on the path to promotion or a raise. So if you work more than that, that's loss. It's silly to say that you can work super hard always collect the surplus. The market isn't _that_ efficient.
