There's nothing that can be done with our tax revenues that would come close to paying for Medicare of All. I have a copy of the IRS's database and the fact is, we'd have to raise taxes on every tax bracket so high that our economy would crash.
My feeling is that we shouldn't add any additional costs to our budget until our representatives come up with a surplus budget that pays our debt down first. We can't afford anything new. We can't afford the benefits we're offering now, thus the reason we're in debt around $22T and growing.
The promises Democrats are making in reference to free college tuition, paying off students loans, Medicare of All, etc., aren't feasible. Unless they're absolute idiots (which they could be), they know that none of these promises can possibly come true. In my book, I call that lying. They use it to stir up their base. They use it to demonize Republicans for not offering such things. That Republicans don't care about their rights (which aren't really rights but privileges). Divide and conquer only hurts our country but let's face it, these politicians have chosen politics over country because it's how they can get the influence and power they desire so desperately.