No. Stablecoins only exist because fiat <-> crypto trading is a massive pain. Nobody wants to own stablecoins, they want easier transactions. And if the USD becomes less popular, people will switch to, for example, EUR stablecoins - there's nothing special about the dollar here.
On top of that, transaction volume is meaningless. Those $27.6T could be $27.6T held in escrow being traded once, or $1 held in escrow being traded 26.6 trillion times. You can't derive USD demand from transaction volume.
RE: Nobody wants to own stablecoins, they want easier transactions.
Agree but that does not mean anything. Stablecoins seem to be solving a problem, and there is not evidence of any traction by any currency other than USD.
So this phenomenon definitely runs counter to the conventional intellectual wisdom that USD is in decline.
Tax evasion could certainly be a use case until govt's sort out the implications. But the lasting use case I think is - fast and cheap transfer of money, anywhere.
On top of that, transaction volume is meaningless. Those $27.6T could be $27.6T held in escrow being traded once, or $1 held in escrow being traded 26.6 trillion times. You can't derive USD demand from transaction volume.