Absolutely, elect enough Mamdani’s and the powerful will not be able to stop the changes. It’s the expectation that a single Mamdani or Sanders can fix much that has lead to extreme apathy from much of the electorate.
That said, I'm sure there are lots of good things Mamdani can do that are not in conflict with reality.
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.
The reason is two-fold: US is subsidizing the rest of the world's medical research, and US healthcare bureaucracy is among the worst in the world.
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.