Very interesting analysis that I think is valid for the next 2-3 max 5 years. Not 30. The caveat of "if [the US] does not sink into political instability" is too mild by half.
The US already has political instability. SCOTUS appointments are for life, meaning the imbalance won't be solved there for years at best.
The US Congress has been punting to SCOTUS for years and this trend has grown. This will lead to more instability in the short run, due to the lag effect of rulings vs. laws.
I could write a whole dissertation on how the end of the Ukraine war might affect the world. Right now Western media is keeping a lid on news from the ground. Russia is winning despite NATO doing everything but openly marching in (covertly NATO is already on the ground).
Right now it looks VERY likely that Russia will take the complete Donbas this winter. Maybe even more territory. That will throw NATO into disarray as the cognitive dissonance in the West is hit repeatedly in the face with maps of eastern Ukraine - or should I say - "former eastern Ukraine."
This at the same time that we here in the EU who "stand with Ukraine" (at the leadership level but not at the public level") will be asked to take in millions of Ukrainian refugees. This at the same time that the US is charging the EU 4X for LNG.
EU leaders who continue to push their public to accept paying for a war we don't want against an enemy that is not ours will go the same way as Boris Johnson and Liz Truss.
The US is still an oil consumer, not a producer (despite the rhetoric). That will limit massively the potential for growth compared to India and China, who will continue to get gas and oil from Russia.
I'll stop here before I need to add a table of contents. ;-)