I think this analysis is spot-on. There is not enough cash in the world to buy all that the US Treasury is forced to offer because of our cascading debt and deficit situation. The buyers must use leverage, hence their need to borrow in the repo market to pay for their purchases, Inevitably, this risks a severe spike in interest rates when these leveraged buyers say, "No mas." This doesn't even begin to consider the crowding-out effect all these government bonds will have on more useful economic investments.
Link: https://www.bloomberg.com/opinion/articles/2019-09-26/repo-meltdown-shows-budget-deficit-has-limits