This is changing the syntax for setting up components, somewhat similar to the class API difference, but it’s still fundamentally the same library. It’s largely just moving functions store on the root object into the setup() function while using a more function-y tree-shaking supporting style.
It’d probably cause as much confusion as it helps.
Rust went through that around version 1 where a massive number of answers were updated to match new release and many got "this is not how it works anymore" comments.
That would be a huge problem. Right now they can just use the API they want and it will work for all the users regardless if they use objects, functions or classes.