This is good news for both bitcoin and the world economy because that slow demise gives the world enough time to "decouple" from America and that has been happening over the past 10+ years, speeding up over the past 2...
This is exactly why for example China is slowly dumping the US dollar and US treasury bonds, or why capital is migrating elsewhere such as to India, or why BRICS was formed, etc...
Without the USA, the world would be at the mercy of the two remaining nuclear super powers, e.g. the dictatorships of Russia and China. Be careful what you wish for. And Bitcoin isn't going to help you if you live in a dictatorship.