>tribes are more tribal
Are they?
My smallish country used to have three or four almost explicitly enumerated tribes: protestant, catholic, socialist and (classical) liberal.
There's a neat table on Wikipedia. Each tribe had its own political parties, its own broadcasting services, its own unions, and so on. My grandpa was considered weird for going to a protestant barber despite being catholic.
They're gone now. The rough shapes remain, but I wouldn't have known it was anywhere near this intense without anecdotes from family and history lessons.
(https://en.wikipedia.org/wiki/Pillarisation)
The US is not the same. Maybe tribes are getting more tribal there. But that might very well be contingent, orthogonal to anything happening to "the West" in general.

Possibly you're overfitting to the US and/or the internet.