The social media companies are probably being very careful about where they base their operations as this can affect what laws they operate under. I don't know how much control a European government can have over a US company, but then Germany has forced Twitter (and I assume others) to include filtering to conform to their anti-nazi laws.

But what about 'old' media? Those are different to social media whose content is created by the users and is more tightly regulated, but very few people control the majority of it. The Murdoch empire is having a massive influence and has probably helped Trump a lot. They may just be turning against him now. In the UK Murdoch's papers have switched political sides before, but are firmly on the right now. Less people buy papers these days, but I belief the right wing Mail's site is one of the most visited here.

We live in interesting times. Maybe decentralised media will see a boom now. Some of the places the 'Twitter exiles' are going to may not be decentralised and that may find it doesn't work so well for them.