Why do you think this is a bad change? I was thinking additional players in the space would make for a more robust ecosystem.
The great value of RedHat was supported software. You could buy one of those $10,000 per seat software packages for some engineering discipline that was guaranteed to work by RedHat and the vendor and if it wasn't they were quite motivated and helpful in fixing your problem quickly.
RedHat also was trusted to monitor and fix security problems quickly, and was in the privileged position of getting notifications about them before they were public so they could be fixed.
The question is how do you get people to fund these two things?
I'm inclined to believe them, with the caveat that this reality may not have come to be had IBM never bought Red Hat. That still doesn't imply IBM forced the change.
It's public record that Paul Cormier has considered the way CentOS worked a problem for years... https://m.youtube.com/watch?v=ITRol3YAV-E&t=360s
For example, LWN's most-recent report[0] on who contributed Linux kernel patches puts either three or four different companies above Red Hat, depending on if you're looking at changesets or lines changed.
Regardless, if leadership is theirs to lose, then they're doing a good job of it.
Kernel contributions are only one metric / piece of a distro, and these days a lot of the code churn is hardware if I’m not mistaken. It makes sense that Red Hat has slipped because the big changes are in new support for hardware.