I disagree. From what I see, company specific stackoverflow like mailing lists or slack channels are also dead.

The normal day to day devs just don’t have the need to go to stackoverflow anymore.

One would have to explain both consequences or dismiss it as coincidental.

FWIW I rarely have the need to ask questions at the programming level to anyone anymore. It’s just not the type of thing I bring up or anyone else. We now talk about architecture and company direction.