This article promotes a popular misconception of the programming situation for defense projects in the 1970s. There may have been "hundreds of specialized programming languages" in existence that could be used, but just a handful actually predominated. Most aeronautical projects were done in JOVIAL. I've talked about this history with engineers from the 1960s-70s. They did not regard the introduction of Ada as a good…
Just the mojo required to print an integer (having to instantiate a generic) was considered complicated
Ada was also very slow to compile, on the order of 10 times slower than Jovial. (my experiences)
Avionics systems back then were tiny. Jovial usually ran on a 16 bit processor.
Ada enabled a certain maturity and correctness to the avionics domain.