I've got a weak conspiracy theory that Twitter has to take drastic action like this because they're not relevant anymore. I don't know a single person who uses Twitter. I don't know that there's a single proprietary thing about their platform that Parler/Gab couldn't copy. I don't know anyone who thinks Twitter is well-designed.

If they aren't centered in the news like they are constantly, I'm not sure that they wouldn't just fade away to competitors.