One of the big changes right after that was offering free private repositories, most people complaining today would've probably not even used GitHub if there were only free public repositories.
Also, the old structure reflected their focus/encouragement of open source, something this change does even more to move away from.
At the same time, I don't view this as a huge issue, though it does make me wish it was easier to get activity details on forks so even if a repo is locked down it would let you see where PRs "went".
Open source projects are the main driver of this change, every popular open source projects gets a lot of drive by AI pull requests that waste maintainers’ time. Projects come up with their own way of blocking people (https://github.com/ghostty-org/ghostty/blob/main/.github/VOU...) but having this be a GitHub feature is a much easier option for most.