There are several reasons for that:
* RH didn't support upgrades between major releases until EL8 (ergo same was for centos). So this feature is relatively new and limited.
* Binary compatibility (being ABI-compatible) with rhel is main feature for derived distros (centos, alma, rocky, oracle, amazon etc). So this is important checklist item during migration.
* Every recent centos-related publications from RH were PR disasters. Every time it looked for community like world ends tomorrow while in reality it always were organisationally significant but not so technically important changes (I'll remind that RH is now in process of making RHEL development public and open and making it downstream to CentOS, not vice versa as it was before).