As the dollar continues its collapse into nothing while carrying all "stablecoins" down with it, why would merchants want to accept it over something that is actually being stable against inflation like bitcoin?
If you visit Cuba you'll find that merchants there will accept dollars for anything. After all its a far better store of value than what their local government has with the peso. This seems the likely outcome for the world too. As more and more merchants wake up to the fact that dollars are being devalued left and right, why would they want to continue accepting that over something that has an actual monetary policy that makes sense and isn't going to be changed by centralized governments?