That's one way to sell a open source project I guess. Not only did Vercel really fight to not have any mention on the React docs about using React _without_ Vercel, but downright to using wording to imply that if you do then you're using it wrong. All clearly states the direction that Vercel is taking React. Soon enough it'll be Vercel-only software.
Yea Vercel being included in this also is a bummer to me - but honestly if history told us anything if they are making some stupid decisions, like completely vendor locking it, it wouldn't take long until a community maintained fork will be created. Same story as Valkey, OpenTofu, MariaDB, NextCloud and so on.
Oh yeah, and there already is (preact, for example). I'm not worried about losing front-end SPA libraries. If anything, I'm just annoyed at the endless greed of VC funded firms.