TV, emailing his supporters, texting them, Parler, etc.

Only Parler is similar to the direct communication of Twitter where anyone can choose to see it. And he is indeed using it to post the removed video.

Plenty of presidents before him have functioned just fine without Twitter, I'm not sure why people are outraged about a single channel of communication, among a sea of countless others, not being available to him is a problem.

It's Twitter, youtube, and Facebook. Obama used both FB and Youtube to get out messages.

And in addition to those three, he still has plenty of other avenues with which to communicate. Again; email, text, Parler, WH.gov, his own personal website, press conferences, TV stations, so on and so forth.

Obama is just one president in a sea of 45 presidents over the course of 231 years. They all managed just fine without tech companies, and Trump will manage to find a way.

Information needs to move fast today. It was the norm for news to travel slowly in the past. Today the president needs to be able to speak quickly to people.

Besides whitehouse.gov, which he should've been using, he has no other way to quickly, directly communicate to any constituent that wants to see his message.

Nothing's stopping him from holding a televised press conference, and he's still not banned from YT or FB.

The video has been banned from FB and YT.

Which means he's not banned from them and is still perfectly capable of using them to "speak quickly to people".

US postal service?

Oh wait...

The alternative is whitehouse.gov or maga.gov or whatever. Does Trump use Twitter/Facebook because they are powerful or are they powerful because Trump uses them?

As well as every press organization in the US.

It's ridiculous that people are actually trying to argue that the leader of the most powerful nation on Earth has no effective way to communicate with the public outside of Twitter.

From my perspective, it was Trump that made Twitter relevant for me.