When the DoD started what became the Ada mandate, they had some insane number of languages and projects scattered about. I don't remember the exact number but think something like 450-500 and this was from the 1960s and 70s when they still weren't terribly digital. At the macro level, that's impossible to maintain. I think a large part of the multi-language dislike came out of that. There is a giant difference between 3-6 languages and 400, it's also harder to get good people once you add a new technology to the stack that they need to know. There are generations of developers and IT/IS guys that have been trained and warned of the dangers of polyculture. That's why people keep doing it.
When the DoD started what became the Ada mandate, they had some insane number of languages and projects scattered about. I don't remember the exact number but think something like 450-500 and this was from the 1960s and 70s when they still weren't terribly digital. At the macro level, that's impossible to maintain. I think a large part of the multi-language dislike came out of that. There is a giant difference between 3-6 languages and 400, it's also harder to get good people once you add a new technology to the stack that they need to know. There are generations of developers and IT/IS guys that have been trained and warned of the dangers of polyculture. That's why people keep doing it.