There's no way for Mozilla to "pull the plug" on a community project with its own leadership and governance like Rust.
And in terms of industry: https://www.rust-lang.org/en-US/friends.html
Re:Remove Firefox Hello from FF49
by scrollaway on Saturday July 30, 2016 @10:32AM
(#12193128)
Rust is one of the best things to be coming out of Mozilla right now. I really hope they don't pull a Persona on it.
I mean the project has it's momentum but in terms of industry it means nothing so i wonder if they will cut money someday like they are doing with these features.