General Discussion

I do think most Democrats have been sincere in wanting to make the gap smaller. The lack of success is that measures that do that are much harder to pass than measures that make it worse.

It is harder to pass a tax increase than a tax cut. This is true even if the tax increase is only on the top, however that is defined. It is harder to create and fund programs that help people than it is to kill or refund them. That is probably the most did depressing. Every program required enormous work to get something that could pass and it can be defunded with much less effort.

Another factor is that even with all laws kept the same, capital if invested even reasonably generates increasing income for those that have it. Limiting the estate taxes allows families to pass wealth from generation to generation.

Also consider that in the last 50 years, the inequality gap was reduced in just one President's term and then only slightly. That was Biden and he didn't get enough credit for it.