At least everyone seems to agree on the necessity of an estate tax.
The consumption tax proposed is idiotic. The problem is that the house always wins, so if I have more money than you and we have equal chances of winning then there's a large chance that I get all your money when we bet against each other (because there'll be flux between which one of us is ahead but you'll run out of money before me). And then you are out and I can move on to someone else. It's simplified but we need to cut to the bone here.
Trickle-down economy is a lie. Over a certain income threshold people start to save and invest more. Investments are good but look at companies like Apple and Google. They have massive cash reserves. In theory they should be investing but there just aren't enough good things to invest in.
Poor people provide more economic stimulus which is why stimulus checks went in equal size to American citizens rather than to the richest. But as the wealth gap increases, the fraction of total money that are "in motion" decreases and economy slows. If the fraction of the US population that buy iPhones decreases from 28% to 14% then Apple is not going to be doing better, are they? Even if those that can afford them become richer.