Nothing in Ada made it impossible to use it on PC or similar devices. And performance of its compiled code was similar to that of C code if not better. And some

Nothing in Ada made it impossible to use it on PC or similar devices. And performance of its compiled code was similar to that of C code if not better. And some of its features like ability to return from a function a dynamically-sized stack-allocated array is still not available in C/C++ or Rust for that matter. I guess what really made it a niche language was the cost of compilers. DoD vendors in eighties already learned how to milk their customer.