In kingdoms and corporations, the more you keep from the masses, the more can go to the king. I think the fundamental reason we need democracy (at work and in civil society) is that humans have a hard time resisting riches for themselves even at the expense of others. Since these workers have no power at Amazon, they can’t effect the changes necessary to improve things. Incidentally a workers union could help here, though I think we’ve made it hard for those to thrive.