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...