Maybe it’s too early for that. Maybe it’s just the right time.
They are doing exactly that if you look at the "Compiler" section of the roadmap[1].
> One project worth calling out in more detail is the RLS 2.0 effort. The existing RLS, while functional, was never deeply integrated into rustc itself. Over the past two years, we have rewritten the back end of rustc to use an incremental and demand-driven infrastructure. To get the IDE experience we truly want, we need to see that work through for the front end of the compiler as well. However, this part of rustc is one of its oldest, and there are significant design questions involved in how best to do that.
> This is where the RLS 2.0 effort comes in. The plan is to build a prototype of the new front-end, thus enabling a truly first-class IDE experience. Wherever possible, we aim to share code between this front-end and rustc by extracting libraries, such as Chalk (for traits), Polonius (for the borrow checker), and a new library focusing on name resolution. Eventually, we will merge this new front-end with the remaining bits of back-end from rustc.
[1] https://github.com/rust-lang/rfcs/blob/master/text/2657-road...
It is not obvious to me what more can the Rust team do here; it would seem like the ball is in the vendors court (or whoever counts as "major player"). Plenty of the groundwork has been already accomplished, and the embed-wg continues on their good work but they can't just conjure vendor support out of thin air