BTW the UK and France resisted that disengagement when they attempted to keep Suez from Egypt in 1956 but that expedition failed, also because the USA didn't like it.
I hope not (!) and don’t think so. We have major natural resources and advantages. I can’t imagine a future where, assuming we mostly withdrew from the world’s stage, that any country would mess with us.
America lives of a constant influx of the best global talent and a global market for its products.
I would bet my money that American democracy would not survive when that ecosystem collapses, especially not as the American system has already transitioned into an anocracy according to some. Collapse in itself would create opportunities, but not for a simple programmer as you refer to yourself.
I think is a bit unfair. The state is the UK and we cooperate with the US but are not especially told what to do by them. I note with Ukraine the UK were the first to supply anti tank weapons, long range missiles, allow strikes on Russian territory with their weapons and so on and the US tagged along after.