The arrangement I have with the bank is very different from my relationship to the fiat system in general. Essentially, the bank gives me me $1,000 today, and I give them $1,300 next year. It's barely any different from when I trade $5 for a coffee. It doesn't keep them solvent in the long term. The bank still has to request that the government print new money on their behalf eventually, like any other corporation.

What I have is a put option on fiat. It only boosts fiat if there's a short squeeze that forces me to buy USD, in order to make good on the payments. It's the longs that are propping up its value, that is, the bond market. And that isn't actually driven by greed or selfish speculation. Institutions buy bonds because conventional wisdom says that's just what smart people are supposed to do. There's no logical reason for it, so its current valuation is extremely fragile.