The world is rapidly homogenising. You see it with “air space” interior design - coffee shops have the same aesthetic in every major city in the world. You see it in local fashions. You see it as a tourist - travel anywhere in the world and the chances are you’ll find the same kind of shop selling the same kind of trinket. Made in China with a subtly different graphic on it to represent the country you’re in.
This has been happening ever since trade routes were established across Eurasia (Silk Road) or the Americas were discovered. It only keeps accelerating as movement and trade becomes easier.
If pockets of humanity could isolate themselves from the rest, we could get diversity growing again, that one sentinel island might be our only hope.