Congratulations to Twitter for discovering only fans, twitch, substack and Patreon. Personally I think this monetisation is slightly in the wrong direction - Twitter provides most high profile users free advertising of their external projects. It would seem more obvious to monetise that rather than trying to duplicate the external sites. No actual content on Twitter is currently worth a fee. Hell, lots of people are quitting even though it’s free.

The constraints of the Twitter platform make it uniquely bad to challenge something like Substack or Patreon, which leaves... Onlyfans as the only paid content platform they can take users from?

Ah so this is why Twitter stock has been on a rocketship recently.

This seems like a pretty good business move. Substack and Patreon have proved that people will pay to support their favourite content producers, and Twitter had the large user base to avoid the chicken-and-egg problem

I don't really agree with the onlyfans comparisons. I think this sounds like a pretty smart move tbh. I cannot imagine a more lucrative ad target market than people who are willing to pay for the right to hear someone they like tell them what to buy.

Countdown to the articles on twitter enabling the sale of child abuse content in 3...

So that means the free Twitter will become more crappy if they will put all the valuable information behind paywall?

Not really. This is a Patreon competitor which exists for sometime. If it had an effect like you describe you would have seen it.