"...leaving the platform virtually unusable for those who remained."
Sorry, but what? I use it everyday and it's fine. Oh I'm sure some of the author's favorite people decided to switch to mastadon or blue sky or something, but to claim the platform is wildly destabilized is hilariously hyperbolic.
As a someone who doesn't use Twitter I've often wondered what its appeal is (or had been) for so many.
Whenever a link lands me there I find tweets constrained by limits on the maximum text allowed. One can hardly state one's case let alone develop an argument in support of it.