The history of Ada kept it from getting widespread attention. Sometimes it’s just about the right time and place.

Plus there’s something to be said for cargo being a killer feature for rust. Easy build configuration , easy package management and access to a large ecosystem of libraries.

Between that and the book..:As steep a learning curve as the language itself has, the actual on-boarding process is way more accessible than many other compiled languages.

Sure, but let's not pretend it is the very first time anything better than C and C++ came to be, and Ada is only a possible example.

Rust sucess story is briging Cyclone type system into mainstream, and in such a way that other languages (even those with automatic management runtimes) started looking at affine and linear type systems for low level performance optimizations.

However for explicit type conversions, bounds checking in strings and arrays, modules, co-routines, assignment before use,... there were plenty of alternatives, which for one reason or the other didn't took off, most not really technical related.