I would say that it failed in its primary goal - to be a single language used for government software.
That doesn't say anything about the quality of the language, just that the goal for it was unrealistic. If the DoD had pressured Microsoft to support Ada in the same way they supported C++, Visual Basic, and vbscript, they might have been able to pull it off. But with the COTS directive and the utter lack of Ada support from commercial vendors, it was just never going to happen.
That doesn't say anything about the quality of the language, just that the goal for it was unrealistic. If the DoD had pressured Microsoft to support Ada in the same way they supported C++, Visual Basic, and vbscript, they might have been able to pull it off. But with the COTS directive and the utter lack of Ada support from commercial vendors, it was just never going to happen.