I read the comment as OP threatening a mass exodus rather than claiming one was already happening. Not clear, though, so it's a valid question. I don't see a mass exodus from Ubuntu but it seems that most Docker containers these days are based on either Debian or Alpine.
Nearly all of the Docker containers I build are based on Alpine. Occasionally I go "oh shit, this uses that musl thing not glibc, I need to remember to... <some minor tweak>".
The one Docker container that doesn't, in fact, is based on CentOS so I can run Davinci Resolve in CentOS when my desktop OS is really Ubuntu.
