I like the Betamax vs. VHS, X vs. Mastodon bit, because technically if you want a safe, high-integrity programming language today, you would choose SPARK2014, the Ada language that has a legacy of mission-critical real-world software projects for decades, proven verification tools and and it is easy to read and write. Rust gained favor with the tech crowd, while SPARK was being used in avionics, aerospace, and other high-assurance software. Why would you choose Rust a relatively new, unproven language (cite some mission critical software that has been running for a decade written in Rust besides a browser) for crypto, aerospace, AWS, and other critical areas? Programming language adoption is just as much about fashion as it is about a true pros/cons in tech.

I think the answer to “why” here is (and will always be) familiarity: Rust bears syntactic and semantic resemblance to already popular languages. Ada doesn’t to the same degree.

(This could be framed as a fashion choice, but I think the more neutral framing is precedence: Rust achieves desirable language-level properties without exhausting the novelty budget for people writing non-government software.)

> cite some mission critical software that has been running for a decade written in Rust besides a browser

This will be hard for anyone to do, given that Rust 1.0 was in 2015, so 9 years ago.

However, if you want examples of Rust running in mature, critical environments: my understanding is that Firecracker has been a key part of AWS’s serverless control plane for years now. Similarly, my understanding is that Windows has been shipping Rust in the NT kernel for the last year.