The Carlson-to-Twitter news tells me two things.

1. He is more interested in influence than money.
2. He thinks his audience is his own and not Fox's.
https://www.washingtonpost.com/politics/2023/05/10/tucker-carlson-fox-news-twitter-elon-musk/

Tucker Carlson makes a big bet on his own power

The former Fox News host’s move to Twitter makes it obvious that he saw his role as shaping the narrative rather than covering the news.

The Washington Post
@pbump 3. He thinks the geriatric crowd is going to figure out how to work Twitter and watch his show on their phone.