The fast food industry makes so much money, more than enough to pay their workers more or even just have bonuses like you suggested, but their goal is to always pay the lowest amount possible.
Sure that's the goal of any business as it is one way to maximize profit, but personally I feel that the fast food industry takes the cake for that.
I forgot to even mention the abuse and how many rules are broken by managers in my article. It honestly makes me upset that I never stuck up for myself or anyone else while working there.