This is true, but you may find that if you had to support something (and keep it relevant) across 20 years those specs and requirements may look much the same w

This is true, but you may find that if you had to support something (and keep it relevant) across 20 years those specs and requirements may look much the same whether they are military or civilian. For example, the amount of bending of the case of a device has to be DRASTICALLY less to allow effectively sealing contaminants out for 20 years vice 2, as well as the seals themselves being an order of magnitude better if there is no servicing involved. For most military equipment we have all of those AND regular servicing, something that consumers would absolutely revolt against nowadays. One other thing people fail to realize on the electronics front: many of the chips in these older systems are getting very difficult to come by. About 10 years ago I was involved in repairing F/A-18 avionics, and one specific chip in that system was extraordinarily important. It was a radiation hardened 80286 CPU, and had a single production run for the entire budgeted lifecycle of the systems it was in. Unfortunately a design flaw in the power delivery systems meant that the CPUs were being destroyed at a rate roughly 4x as fast as expected and they had to figure out what to do. This specific chip was one of the many reasons (but a key one) that we retired that airframe.