I was a CentOS user for my servers, and used Fedora for desktop. Since CentOS as we knew it went away, I've been migrating to Debian-based distros. Couldn't be happier.
Now, I'm not sure IBM will care. I never gave them a dime. But I assume a large userbase is important to get developer support. And developer support is vital to getting paying customers.
Look at Windows phone, which was superior in a lot of ways, but just didn't have the app ecosystem because developers didn't think it was worth it. It's hard to get traction when you have this chicken and egg scenario.
Most businesses IT departments I have worked for mandate a Linux distribution with a big support contract to deploy anything. The Windows System Admins think it will block adoption.
The businesses quickly realised that CentOS worked as a RHEL stand in and all developers can use that.
The logic of CentOS was it was identical to production and so minimised deployment issues but everything deploys in docker now.
As long as I have a Linux based docker host (cause the windows one has weirdness), I don't care what that host is, or how it is configured.
This now reflects in developer environment, I will write guides for Debian (because Snaps), devs can run whatever they want. I specify Ubuntu LTS for production since you can get a support contract for it.