To be fair you'd need to consider how the percentage of young people looked in 1930 for that to be a meaningful comparison to today
You should only be comparing the working age population or maybe even the ratio between that and retirees since absolute population is a deceitful metric.
Japan can easily operate with 60-80 million people in a country slightly smaller than California. And expand again in the future why not?
This. You CAN recover from an economic decline, you can recover from a demographic decline like what Japan is experiencing, but you CAN'T recover from demographic replacement, which is what the EU is experiencing.
I just think there’s something qualitatively different between 64 million twenty-somethings and 64 million eighty-somethings.