Idk if you consider Twitter a big tech company, but they do: https://developer.twitter.com/en/pricing. I don't believe Google or FB does though.

That isn't selling user data. All that is on the site itself, they are just making it easier to access. I'm talking about their click streams and other things that are invisible to the public. That data no one sells because it is how they target their ads.

Twitter is literally selling data (tweets) that users generate via API.

The data is public and available to everyone. They are selling an API to it.