The problem I see is the solution! The solution of taxing more doesn’t work because they just take more jobs to other countries. Technology does reduce jobs but again what can you do.
One problem will be that if there is less and less middle class there will be less and less for that middle class to purchase(cash) so how will the super rich keep making money? It will slow down once the middle class ends.
This has happen in many countries were the rich have left because there is no were to make a lot of money.
A strong middle class makes more super rich! So the super rich do have a problem in the end.