All that an 80% tax would do is suck the wealth away to the 1% even faster. No one is minding the store--the money the federal government takes now at 25-33% is mostly wasted on nonsense that benefits the war machine, the healthcare machinery (think: rent seekers) and all manner of pork projects. I can't see forfeiting even more to them, I just wouldn't bother to work at all. Enough is enough when it comes to this socialist utopia dream--it doesn't exist, it has never existed, it will never exist.
Nobody's pretending that socialised systems magic healthcare out of thin air, it's more a question of total resources spent by society and distribution of outcomes - including whether certain people get rationed out of the system because they can't afford it.