Is there enough economic activity to support it nationwide? I would have to guess so, considering the volume of people who make drastically more than this. What kind of impact would such a massive redistribution of income have?
price increases impact higher-spenders more than lower-spenders
Arguably a high minimum wage would mean no one would want rubbish burgers any more, so perhaps burger flippers would have to retrain as chefs. That wouldn't be such a bad thing.
You can say the same thing about any job. I program. It's a terrible, worthless, respectless job. And yet, they're paid more.
Ha, they'd give up on years of income and pay tuition for that? Nope, I think a lot of people either wouldn't care enough, or just wouldn't be able to afford the opportunity cost. For many of the people whom a 70k minimum wage would affect, college is a financial investment, not a route to lack of tedium as an accountant or whatever.
Surely this would have terrible inflationary effects. Not that I'm against it.