It should be noted that programming languages are different from software.
AWS is paying developers to primarily work on it's needs for Linux (as that is how Linux is generally maintained, you upstream a module, you maintain it).
In Rust on the other hand (like most/all languages) new features tend to benefit everybody, AWS simply might be able to prioritize development of certain aspects, but they certainly don't get to make work almost exclusively for them.
Getting funding and support is great, but the needs of the many are very different than the needs of AWS and Facebook.
In my opinion we see this a lot in Linux as well. What Google wants has almost nothing to do with what I need. (I said almost).
I think it should gestate a while in a less FAANGy environment.