Trump can still speak directly to the voters who are interested. It turns out not very many are interested. E.g.:
https://www.cnbc.com/2021/06/02/trump-blog-page-shuts-down-f...Even Fox has stopped running his events: https://deadline.com/2021/06/donald-trump-rally-networks-ski...
The largest pro-Trump network has seen major declines in ratings: https://www.thewrap.com/newsmax-fox-news-six-months-ratings/