Why? Are we talking population or space? On population, 1900 US population was 75M, current Germany population is 85M.
If we are talking space - what does that have to do with it? And even in 1900, Americans were far more clustered in cities in the Northeast/Cali/etc, so probably not terrifically more area than current footprint of Germany.
Currently we are seeing countries in Europe go through a moral panic over immigration that is probably not terribly different than the US in 1900. I've seen some historical stats that something like 80% of US urban residents in 1900 were foreign born or 1st generation. NYC alone we've had immigrants as ~35-40% of our population from 1900 thru the tightening of immigration laws in 1920s, after which it dropped to 18% by 1970. The percent has rebounded since then and is back around 35-40% again.
So nothing that is going on in Europe is terribly different or unique, and not being a melting pot is a choice that most of Europe has made by being ethnostates.
