Corporate-owned, for-profit platforms, I think you mean. No such thing has happened to Wikipedia, TV Tropes, or Debian. All of these have had their share of drama over the years, with many an angry declaration that it’s ruined forever by one questionable decision or another, but they’re still around and they’re not being intentionally made objectively worse for the purpose of monetizing users.

(I realize Debian is an operating system and not a website, but I mention it because its corporate-owned for-profit descendant Ubuntu is an example of non-website enshittification.)