I think the AC adoption is completely normal and some people really have fun playing astrology and interpreting everything as something more interesting than it truly is.

My house is by no means modern (built by pirates in 1600s) but it's fine 99.9% of the time without AC. So once a year when there's a heatwave, after several days, it may heat up too much inside and then for 1-2 days I walk around pondering "huh, perhaps I should install AC" - heck, if there's that 2nd day I may even Google about different AC models.

But next day heat is gone and I'm like "meh, okay, maybe I will get it some other time" and then I never return to it until the next year's heat remind sme about it again.

Once hot weather in my area becomes much more frequent, I'm sure I will then be finally wiggled into buying AC.

You can already see it across Europe too. Places that had hot weather for a long time have AC: Italy, Spain etc. I have seen plenty whether staying with my Spanish friends or vacationing in Italy.

But I also see it on a local scale too: I live by the sea but my friends living in central London whi often have 5C degrees more already did have plenty of chats about different AC models years ago. They got coaxed into buying AC by frequency of the event.

There is IMO all there is to it. People will just move slow and natural human laziness does not discriminate: old people who may die in this heat will also be caught among those who think they can make due one more year without AC. The only alternative to speed this up would be governments subsidizing or forcibly installing ACs in people houses.

And sure, you can moan about some specific regulations or show some one absurd story from that or this place - but if the real inertia was there, it would happen.