> homogenous country
> homogenous country
This must require a shocking cultural adaptation. In the US, we have many social bonding customs. You'll hear often about how Americans strike up conversations at random, often say "how are you?" as a default greeting, and smile a suspicious amount. There are dozens of examples, but that's because it's baked into the culture of USA as a foundational aspect. I can't imagine trying to shift from essentially Japan to America++ in two decades.
The real trick to seeing the best parts of US culture: Get away from the east and west coasts. Once you go inland, especially to small cities, people are very welcoming. I have seen many YouTube videos were foreigners travel to "parts unknown", and are pleasantly surprised when random people stop to have a chat and wish them a good day. For example, lots of Peter Santenello's YouTube videos[1] are about visiting lesser known parts of countryside US. The people are overwhelmingly friendly (to a fault!).
Honestly, I think a lot of continental Europe isn't so different. In small cities and towns, all kinds of random people will wave and say hello in the local language, even if they guess that you cannot speak their language. Usually, they are excited to see some obvious foreigners visiting their place.
[1] https://www.youtube.com/@PeterSantenello
Where you happen to be born is the only criteria for population diversity?
You have oversimplified criteria for diversity.
right but the entire norwegian society and its welfare state was built upon that homogeneity, where everyone and their neighbor looked "familiar" and could be implicitly trusted to share the same customs. As the foreign born population grows, Norway has taken many steps to restrict immigration, asylum claims, and benefits to immigrants. public opinion has shifted (though not dramatically) as well. parent poster's claim of "easy mode" is receding, so it's not like norway has found a solution to "being a generous welfare state while also openly welcoming foreigners".
Once the enormous diversity-strength becomes undeniable even to the far right and welfare becomes even better I'm sure those restrictions will be reversed.
How much of that is from legal migration from developed first world countries for both countries?
I know I will be downvoted for this.