edit: I just realized this is exactly what USDT is, but I still feel like it will all come burning down at some point. Maybe it will take 30 years though.
This describes like half of finance. Treasuries, bank deposits and credit cards all represent to varying degrees “synthetic dollars.”
I highly recommend this Coursera course to shed light on this: https://www.coursera.org/learn/money-banking
https://www.coursera.org/learn/money-banking
There are also real world examples of currency pegs, for example the Hong Kong Dollar, which is pegged to the USD since the 70's.
edit: I just realized this is exactly what USDT is, but I still feel like it will all come burning down at some point. Maybe it will take 30 years though.