Algorithmic (and I specifically mean the ones meant to drive engagement through rage/fear) social media is the biggest tipping point in my mind, particularly when people started having it in their pockets with smartphones all the time. To a lesser degree, when always-on internet became common.
I think of interacting with people in '26, '16, '06 (no widespread smartphones yet), '96 (no widespread cellphones yet), teens chatting on phones and the newfangled IM thing for those with internet and computers at home, and '86 (though I was rather young) when online communication was still quite niche (BBS's and the like). I would say that that the tipping point came around 2010 +/- a couple of years (probably varying by region).
I would be remiss not to mention the 24/7 news cycle ushered in in the wake of 9-11 (2001) and fox news and such after that also playing in the same dark ways.
Edit: also, third spaces going away changed a lot. We, though moreso people a bit older than me, were involved in community sports leagues, moose lodge (or whatever similar), and other community organizations. This put a lot of people with differing opinions in the same spaces. That doesn't happen nearly as much anymore.
