I wouldn't care to speculate on the first question.
Other than to muse that the U.S. would probably embark on WW3 before giving up that currency status......
What should replace it is a decentralized cryptocurrency that no single state entity or actor could stand any chance of controlling, but there's bugger all chance of the central banks giving up their monopoly on power, that's certain.
Which means that what we'll see touted about is some kind of centrally controlled digital currency that would allow Governments to ditch horribly anonymous cash in favour of lovely 100% traceable transactions.
Money, or rather the ability to create it and control where and how it is used, is power.
Those who have power will use it to keep power. History tells us that they are not usually inclined to relinquish it without a fight. War, death, famine and disease through poverty are the inevitable consequences.
The average lifespan of a 'fake' ie. fiat currency is circa 40 years or so.
By this measure, present currency is overdue demise.
But the longevity varies considerably, from a few months to several hundred years.
They have, however all ultimately failed through spiraling debt-flation bringing about their demise.
I recently read an amazing article about the fact that the world is constantly changing its economic and political order and it is natural and logical. I certainly did not agree with all the details and statements, but overall it looked interesting. And there was indeed information that the US would soon lose its leadership position. And Asian countries, first and foremost China, will be next in the world leadership arena.
In my conclusion, it's possible that that will happen. But not so soon. I think that the dollar will still be able to stay high enough for a long time, because the U.S. economy is quite mobile and adapts quickly enough in the new environment. And this is proven by history and many events that have been and are happening at the moment.
I don't share your optimism.
I assume by "still stay high enough", you are referring to the USD position as the world reserve currency.
If so, I do not think it will be a long time.
The '00 & '08 crises were never resolved... instead the FED blew up it's balance sheet.
They essentially kicked the can down the road, and we have now caught up with the can again.
If '08 was "blowing up the balance sheet" of the FED... I don't know what to call this! lol
The can has been kicked again, but I personally don't know how far it's gone down the road.
I am massively confidant that it wasn't kicked any further than 2025-27 - when the Retirement Crisis comes and kicks down our doors.
We have not yet seen this crisis in all it's glory.
We had a recession coming anyway, but then the virus sped that up.
People have gotten used to the virus and think we are over it, but people are confusing the virus as being the real problem.
Unemployment is at very high levels... Debt is astronomically high... credit is extremely hard to come by.
The world is built on credit!
The stock market is rising, which is giving people the impression that things are recovering.
But in fact, it's worsening!
A large part of the index is made up of about 5 tech companies which did well during this crisis.
Then you have the FED buying all sorts of bonds too - this was unprecedented and cannot last.
Economically speaking, the worst is yet to come.
China has become a real powerhouse, and it ironically supplies the US with much of it's purchases (including meds)
There is no way back for the US... the best they can hope for is to survive another day... to recover and rebuild - just like China did when it fell from grace a long time ago.
Also worth noting is the amount of gold that Russia has been accumulating
They fell into the abyss a while back, but they have been quitely building themselves back up too.
Big changes are coming in the next few economic cycles