If US debt-to-GDP is such a problem, why aren’t US Treasury rates surging and other fiat currencies surging relative to the dollar?

Because the FED buys it suppressing the free- market to speak! That will translate to inflation. 

Least worst option. If your house is dirty and all other houses in the neighborhood are even dirtier, that doesn’t mean that your house is clean.

🇧🇷🇺🇸-  Book: Making Things Think: https://holloway.com/mtt. Investor in Wander, Carry, Footprint, Merkle Manufactory (Farcaster), Dynamic, Paragraph.

But why aren’t sophisticated large scale pools of capital betting against that?

Betting against the USD, debt to gdp, cost of US borrowing will materially increase?

Sorry, I didn’t understand your question. Betting that inflation will go up?

What’s sophisticated large pools of capital? Blackrock? (They’re dead if USD goes). 
Sophisticated macro funds do bet against the US although they rotate in and out of those positions - see Druckenmiller, Gundlach.

Also another point that I’ve been thinking is that there is one currency that is performing better than the dollar consistently. That’s bitcoin ☺️