As Reddit banned all its creepy communities, people had a fit for a few days and made similar proclamations about how Voat would beat them as a result, and then life went on. It didn't destroy Reddit at all. Same with the crackdown on the conspiracy subreddits. Off they went to Voat. But Voat is gone and Reddit remains.
Twitter ended up banning Donald Trump and people discussed how it would be a watershed moment that would spawn this massive backlash and fuel Parler and Gab. But Twitter remains king. Parler and Gab haven't been something I have heard of in months.
All of these claims that a ban will cause significant damage to Twitter require people to fear that they will be next. Does Substack really have that kind of reach?