As to Ada... I've coded in Ada too back then, and I know of some big code-bases that are rock solid in Ada. Unfortunately, there is a severe shortage of Ada programmers who are willing to maintain those code-bases, so what happens is that a lot of money is being thrown at converting all that Ada code to C++ code, using semi-automated tools where possible. This auto-generated C++ code is then manually re-validated by C++ hackers (and that's what is so costly), and from here on, it will persist as C++ code, maybe for decades.
That's the way it goes. A language may have merits of its own, but if it is not popular and if you can't get enough people to maintain your sizeable code-bases, that language is ultimately of no use. C++ seems like a good compromise between openness, royalties/patent-lessness, speed, type safety, maintainability (when done right!), and long-term maintainability through coders. Despite its known shortcomings. No Rust, not even Ada can beat that.