Money

There is only one reason why money exists, and that is power.

If you have no money then you become powerless, whereas if you have lots you become powerful. This is a huge over simplification I know, but the problem isn't the gap between rich and poor, the problem is what do you replace money with in order to create total equality.

Money could be replaced by time, as time is something we are all born with, though I grant you that lifespans differ from region to region, so there would still be an inequality.

For the present money is all we have until a replacement is found that creates equality.

But you have to admit that those whose bank accounts are overflowing will be somewhat reluctant to see all that wealth become useless.