This thread is making me wonder what Britain could have done differently to survive. England is not a very large island. Frozen in amber, it would disappear from all relevance.
I suppose the UK should NOT have built the Tunnel, should NOT have joined the EU.
I suppose they should have banned birth control and sent their excess to the former empire, rather than the reverse.
The Ancient Greek Democracies are gone, never to return. So it will be with the British Empire and even America. It must be unsettling to see a height of civilization that is in your past, but the past never returns.
Old Britain would have modernized its industry and either held on to some of its colonies or ended up running Europe, but New Britain didn’t have that kind of energy.