We DO have double pane windows. Just not in areas that have middling weather. Or construction before 1990 or so. Or in older mobile homes, which we have a lot of. And the houses with double pane windows are often poorly constructed, sometimes in the homes, sometimes in the windows, and often both.

Energy has historically been very cheap here, so efficiency has never been a priority. That is changing now.

The videos I’ve seen of northern European windows just seem to have a ton more features than ours.

You should see the difference in available windows in the states vs Europe. Its like you are in the 23rd century and we are still in the 19th. Our boomer class raced all the way to the bottom to increase profits, so many things are just cheap plastic here. We can special order windows like you have, if you want to spend $4000 per window.

What you consider normal is exotic here.