I can't speak for everyone, but I'd say that I've noticed that younger devs simply do not chat.
My team rooms are pretty dead. I'll send stuff there but by and large the team simply doesn't use chat functions.
Partially thats about teams and how most corps use it, which is built primarily around information siloing and management visibility.
They, for every team I’ve ever managed, have an off company owned systems chat on shit like slack or discord where they are roasting the fuck out of you.
I’ve managed to be invited or told of them after ingratiating myself to the teams, or more often, after quitting and getting invited as one of the “good ones”
They all know that every word on company shit is being monitored
It doesn't help that reporting people to HR is a way to career advancement.
Perhaps the youngins are more cognisant that it's all monitored. Knowing your employer can read everything and it _will_ be used against you has a chilling effect and I'm pretty sure that's part of it.