These systems are typically developed in public-private partnerships. This is not really the same thing as "the government" creating it. The projects or technologies are typically evaluated by studies which, even if classified, are frequently conducted by private corporations contracted by the government; the research is undertaken by a mix of government and industrial labs; and then manufacturing is generally (though not always) undertaken wholly by private enterprises.

The government and industry both have a role to play. Maybe part of the reason the myth persists is because it is simpler to believe it's one way or the other -- government creates technology or private business creates technology -- than to think in terms of the more complex reality.