They're missing quite a bit, actually. Like how Rust had a bunch of contributors even before they started, and Mozilla Corp. backing them. Rust's solution is only viable if someone wants to bring those to the table along with it; it's just not possible otherwise. There aren't enough people *now* to build a whole new infrastructure.

I work with another open source project that is as short on contributors as ghc is. It's part of my day job, even, and it's a regular topic at team meetings. One comes to understand why this is not something that can be done on a whim. (And my employer isn't big enough to do the heavy lifting or provide bodies --- even ignoring that we feel it's best for us and our customers that this project remain independent, not controlled by or beholden to any company, which makes contributing somewhat difficult as a political matter although we do our best.)
--