Someday Germans will discover air conditioning. It's standard in 90% of homes in the US (close to 100% in the south). Japan and China, too. Air conditioning is weirdly uncommon in Europe, but I've heard stories that it's especially rare in Germany.
Yeah, no air conditioning needed years ago. They do offer air conditioning now, but with the insane electric bill prices I'm sure most hesitate.
On the other hand we still have small fences on rooftops to prevent snow from sliding down. They are useless now because we don't get much snow anymore.