I think you're misreading how much an elderly ultra-famous and quite rich author gives a shit about his "status" on some stupid website like Twitter.
I think he was insulted at the idea of having to pay anything to be verified on the platform, when both his presence and his being verified are helpful to twitter and make twitter money, even if they do also drive some book sales for him. I took it as his saying that he'd respond to such an insult (being asked to pay) by simply leaving, because Twitter and whatever little extra money it's making him don't really matter much to him.
I doubt he's alone in that thinking. Though sure, some celebs, most or all brands (that's who they should be soaking with monthly charges), and the media will stick around until/unless the platform enters clear decline and a viable alternative emerges.
Yeesh, what is with the Twitter/Musk fanboy crowd and journalists and blue checks. It's such an unhinged and nonsensical hatred. Reeks of being jealous.