I have a comment above about access to capital, which is much easier if you already have it, so the rich have more access than the poor to the main tool of capitalism.

But another example, equity: If I am raising money for my startup, and I have no traack record (I'm poor in this context) and Sam is doing the same after Sam made a successful exit from their last startup, who would you invest in, all else equal, Sam or me? Sam if you are rational

Thus the rich have more access to equity than the poor

This is a pattern that repeats over and over in free markets