[0] has many more details but CentOS was never a drop in replacement and the new CentOS model is a big improvement for anyone wanting drop in replacements. I agree with everything else you said though, they were independent of IBM for nearly 3 decades and always were and still remain among the most active linux contributors (just see any of LWN's development statistics articles).

0: https://medium.com/@gordon.messmer/in-favor-of-centos-stream...