If Ada/SPARK were to be successful, they would need this corporate backing. Maybe that's possible outside the USA? Say, the EU probably has enough influential tech companies and weight to push forward with a Rust competitor that's perhaps superior (as you claim, I don't know enough about SPARK yet to make that claim myself)? I think that would be extremely benefitial to both the tech world AND to Rust and Ada themselves... competition is a great way to make things evolve fast.
EDIT: Ada/SPARK does seem to have a really good advantage over Rust: it's an actual specification, not just a single compiler implementation where "whatever the compiler does" is how the language behaves. This is very important in many industries. I know there's work ongoing to fix this for Rust, but that may take several years and even never amount to anything.
http://www.ada-auth.org/standards/rm12_w_tc1/html/RM-TOC.htm...
But I have worked at companies that transitioned (or started to transition) from C/C++ to Ada/SPARK and from C/C++ to Rust. I suspect that there are a few additional factors besides politics that prevented some C developers from taking Ada/SPARK as seriously as they seem to be taking Rust.
1) Ada and SPARK still retain a whiff of academic/military design-by-committee which prejudices a certain kind of developer. Whereas the Rust team has been open-source from the start.
2) The military projects I am familiar with started switching to Ada (and later SPARK) due to the US DoD mandate in the 90s. Of the people I know who use it, many of them started using it because their job required it. (Though to be honest many of them now love it!) Whereas Rust adoption seems to be largely driven by a hearts-and-minds initiative to convince regular developers that memory safety is a problem in C, and that they should choose Rust to solve that problem.
3) Syntax. Some C developers don't seem to consider a language a Serious Programming Language unless it uses curly braces. (Just ask a C/C++ developer about Lisp's parentheses or Python's whitespace.) Whereas the Rust team decided to hew close to the conventions used in C wherever appropriate.
Excuse me? Do you know about Ada/SPARK? Rust is super far from Ada in terms of safety. I see misconceptions about Ada here all the time. Well, either that, or they do not know much about the language. Seriously, if you are interested in safety, you must check Ada/SPARK out.