"There is a constant American assumption that their language and culture is the norm"
This is now far more than an American assumption. I have seen younger continental Europeans bristle at UK English because they grew up in a world of social media that is converging on usage that is closer to US English.
Real question: Post 2010, are there any non-English speaking nations that get most of their English language media from the UK? Since everthing went online after 2010, I assume US has the highest influence (linguistically) only because of "mass". Dear UK readers: Please don't interpret my comment that UK language culture is somehow inferior. HN knows and loves UK humor!
This is now far more than an American assumption. I have seen younger continental Europeans bristle at UK English because they grew up in a world of social media that is converging on usage that is closer to US English.