Most families that own a house owe substantially more than 1 year's income.
Last time we reduced the annual deficit to zero, the usual debt hawks all reversed their position and said "this is terrible". We've demonstrated in my lifetime that we can do this. The fact that "we" don't want to right now has more to do with Republican attitudes towards taxation than anything else.
MMT says we don't need to think about this the way we think about personal and corporate debt.
It's not that there's nothing to see here, but the sky is not falling.
Now, the stock market overvaluation ... that could be a real problem, but not the same problem.