I think that just because someone hasn't quit isn't evidence of their contentedness with their pay. Chinese sweatshop workers keep showing up so they must like it.
I do believe that executives would act in their own best interest. And since they direct the company, I have no problem in believing they would act in such a way to increase their own incomes. I would furthermore, seriously doubt that they would act in a similar manner on behalf of employees (not that they should). But I think blind protectionism of Wal-Mart is as unreasonable as wild fantasies about nefarious Wal-Mart money making plots.
the average walmart worker isn't going to starve if they quit. hardly a similar situation. america is not rural china.
the shareholders own and direct the company. it is not in their best interests to pay unwarrented salaries to the executives.