There are plenty of examples in the world to turn to to learn what happens when you get a critical Mamdani-Sanders mass. They tend to be rather unpleasant examples which are usually done away with using a variety on the "true socialism has never been tried" claim. No, Mamdani will not be able to turn New York into Caracas just yet. Let's all hope that nobody will be able to accomplish this.
There's no reason we should pay 2x what everyone else does, and live 10 years less (for healthcare).
We could accept a good deal of socialism into our system and see only benefits; there are a number of things which should not be profit-motive driven at all.
Most of the basic medical research is funded by tax dollars.
Also, are you sure the bureaucracy isn't exactly the point? If you're too sick to fight off a denial and die, they keep the money.
I think we're subsidizing Wall Street's profits with our garbage system, but the sooner people realize our system is totally failed maybe we can knock it down and do something else.