The rant is probably around convenience. How hard is it to offer one-click migration of your data from one account to the other? I guess pretty hard, since they don't support it.

My example is Google Play Music, which they migrated to Youtube Music. They probably offered to merge accounts at the time, I don't remember, but I ended up with two Youtube accounts with different playlists that I couldn't merge or transfer data easily. I had to do an annoying dance to recreate my playlists from one account in the other.