What you want never existed in the first place. Not only because of those other subreddits you mention, but because Reddit was not the entire sum total of RPG discussion on the Internet. The RPGNet Forums, TheRPGSite forums, RPG PUB, EN World forums, RPG Codex, and innumerable other smaller forums were scattered all around the Internet. You never saw them or their content because none of them are "federated", and so you thought Reddit was the center of the RPG universe.
We now have an opportunity to restructure how diverse separate fora like that can work. If they were all federated then you'd be able to seamlessly view content from all of them, and communicate back without needing to have a separate login at each and every one of them.
If you really want to continue treating /r/RPG as the center of the universe and ignoring all the other fora, well, these new ones on the Fediverse merely add a few more onto the enormous list you were already unknowingly ignoring.