Simple Math : Nope. Actually M4A is a very very complicated issue, it's only simple in Bernie's head. You're asking a very prominent industry (Medical, pharmacy, insurance) to all play mother Theresa so that (excuse the langugage) poor BAME and Poor homeless white can enjoy getting hospitalized. It may be a grand gesture, but if you're not homeless, you're not minority, and you already have an insurance / health plan, why risk it all? It's far from simple math, there's no model that can get close to predict what will happen under M4A because the variables are too big. It's more than "Net positive collectively"
common decency : You think the majority of Americans cares about homeless and the poor? again you're assuming Americans are decent, as trump have shown they're not. And as Biden have shown, half the democrats too don't have the decency for this. And Brexit again have shown that half of England gives no two feck about honest immigrants want to pick fruit for the benefit of everyone in a win win situation. Nope, off you go lad.
Climate issue : again you seems to be failed to grasp why Trump wins the last time around. When Democrats talks about LGBT issue, equality, Iran, world climate and all the usual political mambo jumbo while Trump talks about Jobs, how poor you fellow are and I'm gonna fight for you, even if I have to feck everyone else up. That's right folks, you' think majority of america cares about climate change? They want Jobs, they want economy, and while Trump fails to deliver on both account he didn't fail to address it, and if I'm a poor working American in rural I'd pick Trump any day and twice on Sunday. You remember what Trump promises during his campaign? He's gonna rip stupid Climate Issue and he did that on his first day. Like him or hate him this is what Americans wants, they don't care about some climate change.
Read my answer again, I'm not saying I love trump, or I hate Bernie, but looking from the outside it's clear to me why people don't want him (and at this point this is not my assumption, democrats don't want him either hence they vote for Biden). And it's not because he slipped "socialist" word back then. It's because frankly speaking he offers nothing concrete other than some old man pipe dream. And it's not misinterpretation either, even John Oliver and Bernie's own base are scratching their heads on what/who/where/when/how M4A could work. We're talking about redoing the whole American health care system, and that's assuming the Republican didn't throw a wrench and sabotage it halfway. I don't trust the democrats to do all this if I'm american, they can't even properly impeached a buffon.