It seems a plausible concern with Colbert, but doesn’t explain Conan or Corden.

So I think there’s some ambiguity here and some potential to look silly declaring this with absolute certainty and then Colbert ends up explaining he wanted to retire or move on to other projects while handing the show off to some other host, but the network decided not to bother with that show after the current host goes.

Meanwhile more unambiguously Trump has been restricting access to news media he doesn’t like and we can keep talking about that and other unambiguous things and even saying there’s a solid chance that appeasing Trump is to some extent causing this event, but certainty needs more information from authotive sources.