Why Ada failed has been discussed ad nauseum including on here. Early compilers were $$,$$$ per seat and proprietary, they're still easily $,$$$ per seat. Good open source compilers came later, there's still a strong disparity between the FOSS and commercial compilers and tooling.
The language was a mandate from US DOD which rubbed a lot of people the wrong way. It largely sat in the same space as Fortran and C, C was free (or much less expensive) and more readily available even when it did cost.
Cosmetic: People strongly dislike the verbosity of Ada. Some parts are reasonable to consider changing (but really are just cosmetic) like begin/end versus {/}. Other verbose portions are hard to change without fundamentally altering the language. You want to print integers and strings and you don't want to have to use Integer'Image(X) all over the place?
with Text_IO;
use Text_IO;
with Ada.Integer_Text_IO;
use Ada.Integer_Text_IO;
NowPut and Put_Line can be used with both strings and integers. Oh, you want to print more types? More withing for you. I don't mind it, you don't need to print in every package, but it is very cumbersome.
If you want to write a quick CLI tool, Ada is not your language (though I've done it), go for Perl, Python, Ruby, sh/bash, or even Go. C and C++ can be easier for that purpose. But once you start scaling it's a very good language.
The only way to get Ada in the mainstream now is to make it much cheaper and greatly improve the FOSS compilers and tooling, and have SPARK/Ada support an increasingly large subset including approaching feature parity with respect to memory safety as Rust. That's being worked on, but it's a non-trivial problem.
The language was a mandate from US DOD which rubbed a lot of people the wrong way. It largely sat in the same space as Fortran and C, C was free (or much less expensive) and more readily available even when it did cost.
Cosmetic: People strongly dislike the verbosity of Ada. Some parts are reasonable to consider changing (but really are just cosmetic) like begin/end versus {/}. Other verbose portions are hard to change without fundamentally altering the language. You want to print integers and strings and you don't want to have to use Integer'Image(X) all over the place?
Now Put and Put_Line can be used with both strings and integers. Oh, you want to print more types? More withing for you. I don't mind it, you don't need to print in every package, but it is very cumbersome.If you want to write a quick CLI tool, Ada is not your language (though I've done it), go for Perl, Python, Ruby, sh/bash, or even Go. C and C++ can be easier for that purpose. But once you start scaling it's a very good language.
The only way to get Ada in the mainstream now is to make it much cheaper and greatly improve the FOSS compilers and tooling, and have SPARK/Ada support an increasingly large subset including approaching feature parity with respect to memory safety as Rust. That's being worked on, but it's a non-trivial problem.