The US is generally much closer to the equator and warmer than Europe, hence air conditioning has been a requirement for much longer.

https://vividmaps.com/comparing-latitude-of-europe-and-ameri...

US states like Texas and Florida have no latitude equivalent in Europe. Los Angeles is farther south than all of Spain.

At the same time, the UK, much of Germany, and Poland are farther north than any state in the US lower 48.

And yet, even here in Oregon many of my coworkers only got window AC units during a heat wave a few years ago. But let's not break the narrative of all US vs all of Europe.