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.
Their globalist friends want more immigration to drive down wages and increase rents.
This is nothing at all like in the U.S. The U.S. is huge and I'm green with envy when I see YouTubers owning whole estates in Idaho to make their private aircraft videos. Such things are completely impossible in Germany.
Then there is the cultural aspect of course. The U.S. has been an immigration country from the start. Europe had diverse hand highly advanced cultures in music, paintings, literature etc. Frankly, since the Americanization following WW2 neither Europe nor the U.S. have produced anything comparable.
What you call ethnostate, which is a derogatory term, other people call culture.
I don’t think America has been a melting pot from the start. It was Protestant whites and slaves for 100 years or more.
Letting in Catholics and Jews was a choice and controversial at the time. Then the same for East Asians, South Asians, MENAs, and the latest drama is Latinos. I probably forgot many other groups. Different choices could have been made at each juncture. Continuing on this trend was a choice.
Germany continuing to not be a melting pot is a choice just the same as deciding to become one.
European wages are a different issue and it is to me more a problem of thinking you can tax and regulate your way to prosperity. Letting in more or less immigrants isn’t the primary problem.
Why do Americans and foreigners want to start companies in the US so much? Where are the European startups? Are any Americans moving overseas to start companies? No new firm formation leads to no new job creation leads to lagging economic growth.