I don’t see how changing the name helps over a version number.

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.

Because it's essentially a different project at that point. All stackoverflow answers become confusing instead of helpful for example.

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.

Making it two separate project means the library authors have to write two separate libraries using two separate API - the more flexible and easier to maintain (written among others with library authors in mind) function API and the object API that they often have to fight against right now.

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.

I see, I don’t help people often with programming problems so I’ll defer to you guys.

You would get Google answers that are specific to your current version vs wondering if it applies to Vue 1, 2, or 3.