There's this strange belief a lot of people have that leaders care about regular folks. They don't, they only care about themselves, and the system as it is is what got them where they are. Thus, they are incentivized to keep things the way they are. Not just that, but in a plutocracy like the US, leaders want to make sure that poors stay poor. The worst possible outcome for the rich and powerful is that it becomes easier for other people to climb the ladder, and harder for them to increase the size of the gap.