I’m sure that Rust will continue to become more complex, and in 20–30 years another systems language will likely come along that is at least as safe while being easier to work with again.
Which is very logical. If you add Rust, why not Zig, Nim, and every other low level language?
A lot of pain and drama could of been prevented if he put his foot down and said only C code is allowed. Instead he left it ambiguous, and a lot of good meaning people have been damaged by this. I know I'd be upset if I had been a part of the Rust for Linux team, and when I actually wanted to get my code in I was told my contributions weren't welcomed.
I wouldn't want to mix and match languages in a project that's so vital to really the entire world. It just seems like a good way for a funky rust bug to cause billions in issues...