I don't think its that surprising. Essentially what happens is, engineers do a good job and keep getting promoted. If their service is required/essential, they continue to get funding etc. until they reach such a stage that they know their systems through and through. They're also at a point in their lives where other things take priority (most of the times its children).

I don't particularly find this situation to be bad. They are doing the tasks assigned to them, and there is a defacto agreement with the management that they have other things to take care of as well, but will get a ton of shit done when they do work.