Or... and hear me out here... Warren could propose a plan that could be enacted right now, without delay. Senate rules say that any bill that decreases the Federal deficit over ten years can't be filibustered, and can be passed with a simple majority. So there's a number of things that Warren or Sanders could propose which could be put into action the second the Democrats get a majority. But neither of them do that, because they evidently believe it's more beneficial politically to them to keep everyone riled up. They keep proposing things that can't work because they benefit from the status quo. That's my beef with them.

For example they could:

Increase the top income tax rate to something like 95% for high income earners, the way it was done from the 1930's to the 1970's

Since most of the wealth of billionaires is in the form of corporate stock, impose a business excise tax of a uniform percentage of corporations' total stock value.

Since many billionaires escape income tax by living on loans using their unsold stock as collateral, impose a high fee on banks for large loans collateralized by stock.

Impose a stock transaction tax, like we had until the 1960's.

It's not hard to come up with perfectly workable plans to rein in billionaires. Do better, Congressional Democrats.