Depreciating currency would help, or permanent negative interest. Then the default behavior of wealth would be to shrink, rather than grow.

The deeper problem is that wealth is power, and power can be leveraged into greater power. I can't see any way to fix that except a culture where it just really bothers people to see any differences in power.

In hundreds of years, if we manage to eliminate all suffering from lack of food, health care, etc, the next thing might be to eliminate the suffering of lack of social influence.