Chat supports rooms with chat threads without autodisappear. Everyone is in various rooms for their local team, broader team, org, and cross functional stuff. The net effect is Slack-like.

There's also the ticket system. Sheets are commonly used by various PMs and TPMs for high level tracking, but IC eng stick with the tickets.

It works fine.

That was the case from 2011-2016. I can't say with as much certainty now, but anecdotally, probably similar.