Hey Kai,
thank you for the comment and good question. I would assume testnets are excluded. Let's see what this brings.
Twitter Blue costing money will definetly change a lot. In the end it's a thin line, either the quality of content will rise or a paywall will hinder people from participating. Since Google+ we all know what a social platform without participation ends like.
High NFT prices on the other hand could also ignite NFT-Creation due to this new feature and flood the NFT market, which will also affect the prices.