Not all stablecoins are based on US$
But 100% agree with your analysis.
My prediction is that stablecoins will replace national currencies, most countries will have their own, these stablecoins will be pegged to each country's bitcoin and resources reserve.
Bitcoin will become the global reserve currency.
I don't think that anyone or any group is powerful enough to stop Bitcoin from becoming the global reserve currency.
And if the stablecoins aren't based on Bitcoin reserves and resource assets like gold the stablecoins will become totally worthless over time as with regular digital fiat.
I don't think physical currency will ever go away, when fiat becomes worthless or all of it becomes digitalised people will find something else or use barter to some extent.
By the time Bitcoin becomes the global reserve currency there just won't be enough Bitcoin to replace physical cash in most countries.
Governments will be seizing people's wallets, creating regulations and licencing for node running and mining scrambling to catch up because they aren't investing now.
Investment firms like Blackrock that are investing in btc are going to make the east India company seem like nothing in comparison.
Countries like el Salvador, Nepal etc. that are investing now.
They'll be the only ones that can afford to use Bitcoin.
Blackrock and others will probably issue their own stablecoins that will replace currencies of countries that don't.