I agree with this assessment, to me Mel has had a lot of repeat offenses over the years and has been warned about it repeatedly until the corpo had no option but to cut their loses.
I mean... despite how people react to them, graduations are inevitable. One day all vtubers WILL graduate, since they are played by real people and the character dies once the person moves on, everyone will someday move on with their lives, it's an inevitability.
I get why fans view "graduation" as such an indictment against corpos, seeing it as PROOF! of malpractice (which admittedly it often is) but graduations will only become more frequent as time goes on and more vtubers either fall out of the hobby or age out of their careers in this industry, and I think Cover has done good in being able to systemically soften the blow to the fanbase, some people will of course forsake Holo for slighting their oshi, but that's to be expected.
Not really true with Mel since she was already more popular on her roommate persona.