I am not sure if a country will have some sort of bitcoin standart but I am pretty sure we are moving to a level where countries will have their own stablecoins which then could potentially have some sort of limitation just like bitcoin having 21 million max cap, those nations with max cap stablecoins could potentially back their money with that stablecoin and that would mean there would be some sort of gold standard type of deal where it is limited and depends on how much people value it.
If USA one day came out and said they will print out 1 trillion dollar worth of stablecoin and that it will never be printed more than that, people would buy it and hope that it would go up in value, sounds like it could "kinda" work. There would be ton of details but certainly better than current "backed by nothing" system.
The things you saying are contradictory with each other. First problem, stablecoins are not capped. It doesn't make much sense to limit the production of stablecoin. In order to measure the increase/decrease in the value of any commodity, you need a variable which changes with the value. Currently fiat money serves that purpose. Suppose, the price of 1 kg onion is $5. Now due to decrease in supply, owning onion has become difficult so price will rise, say to $10. Similarly, the value of all commodities change and such change can be exponential. If the variable i.e. fiat money is limited then you won't be able to measure the increase in value after a certain point which is not right for the economy.
Second problem, the problem of growth. Why do you think price of an item increases? Or salary of an individual increases every year? The underlying problem is the problem of growth. No one wants to remain at same point for all his life. Everyone wants to grow. If you have $100 today, you want to have $150 tomorrow and may be $200 a day later and so on. The concept of growth has given the birth to the concept of inflation and so on. Now if we limit the production of money like you saying, $1 trillion in US Economy. It may sound great solution for now but what about 100 years later? How will US measure its GDP growth once economy will touch $1 trillion mark? You always need an infinite variable.