For a different view

I don't think this is the reason or atleast the only reason. Red Hat has stopped funding CentOS developers full time to work on replicating RHEL for free but the sources including the git repos for all the packages are still available and they even did the work in Fedora (which RHEL inherited) to make rebranding easier. With the open sourcing of the build system and management tools including Koji and all of the components behind Red Hat satellite, they aren't holding back on anything there. They don't have to do all this if the goal was to prevent rebuilds. For all the permissive licensed components, they aren't required to publish anything at all. They have gone well beyond their legal obligations.

The stated reasons of having CentOS as it exists now play the role of a more closer upstream that they can build out of seems to be the right value proposition for them. As usual, they botched the way they have announced it and explained it however. What would have been logical is for the RHEL subscription changes to come first, CentOS 8 Stream (and not CentOS 8) to be announced and explained clearly with the current intentions transparent so people can plan around it better.