What do you mean it hasn't failed?
You show a web-site dedicated to Ada ... so what?
I can find web-sites dedicated to Latin.
You know ... the stereotype of dead languages.
Try searching on dice or monster for Ada jobs.
You will see that Ada is a dead language. Maybe except
for PL/SQL except maybe that PL/SQL is a sibling of Ada
Both being children of APL.

I work at a place where the "technical lead" brags about translating code
written in Ada to Visual C++ and then taking credit for implementing everthing
else in PL/SQL!