I would not declare America dead. The USA has good demographics and if there is a shift in politics back towards original American values of freedom and free markets, such a system will always dominate those autocratic shit shows called Russia or China. Maybe the USA will not adopt bitcoin as reserve currency tomorrow but I see a possibility for a gold standard (that might open the backdoor for a bitcoin standard later on) which would already be a huge thing.

The Roman empire also bounced back after the crisis of the third century and even later Justinian was close to reconstituting the old empire. The real world is messy and nothing is set in stone.