Not actually Larry Sabato, fwiw... but still, the same is kinda true of Fox News where people are shamed if they don't use or consume the product under the guise of "understanding" the other side.
Life is short and discourse on Twitter, while never great, has become really really toxic. Particularly if you end up on the "For You" tab, which the app seems to push me toward every time on log in. The ability to use the product to the product as a news aggregator for things that aren't politics has steadily gone downhill in the time since Musk has owned the product, undoubtedly in large part to changes made (such as eliminating blocking, among other things).
Maybe the explanation is as simple as the product just sucks and has gone downhill, just as has happened to many brands over the years. And maybe alternatives are picking up steam because they provide a different experience for users who don't have time or inclination to wade through all the BS that the current environment that Twitter throws at you. In other words, the market is doing what the market does.