I'm not advocating for this, but it's a example of a position reasonable enough I'd expect to see some level of support for. I'd view it as less extreme, for example, than requiring all new security-relevant code be in Rust, which is certainly something I've seen argued for in various contexts.

While not "only Rust", that development should be done in memory safe languages is the position of the US Government:

Held both weakly by CISA:

https://www.cisa.gov/resources-tools/resources/memory-safe-l...

And more strongly by the NSA:

> NSA advises organizations to consider making a strategic shift from programming languages that provide little or no inherent memory protection C/C++ and assembly, to a memory safe language when possible. Some examples of memory safe languages are Python, Java, C#, Go, Delphi/Object Pascal, Swift, Ruby, Rust, and Ada.

From https://media.defense.gov/2022/Nov/10/2003112742/-1/-1/0/CSI...