This a really good question I would add the space program to the question but that is just me. We would be a great deal farther behind. Especially Aviation and Space Flight. Many many things were invented or joined together to fulfill a role in the military. A good example is the GPS system. This wasdevelopedfor the USA funded by the USA etc. It overcame errors in land sea and air navigation instantly when released by President Reagan to the public. It revolutionized how First Responders arrive at the scene of incidents reducing both time and costs. However originally the public version only got you as close as 3 yards but not dead on like we have today. Of courses in the field of Trauma and Emergency Surgery the Military Hospitals excel and teach many young doctors move on to the civilian world and to Level One Trauma Centers to deal with civilian casualties. The military is a great proving ground for a lot of platforms. It also weeds out the products that don't live up to design standards. As a side note this is not always good. It is said that NAZI Germany advanced sciences like genetics by 5 to 75 years but they were performing their research on love human beings. They also advanced internal medicine and even made the first in cigarette smoking and cancer. But they were dissecting live Human Beings. A great amount of information was gained after the bombing of Hiroshima and Nagasaki with atomic weapons but look at the costs in lives. The birthplace our space program did not start in America it started in Germany. After the war we gave the rocket makers a free pass on war crimes if they woulde to America and build bigger better rockets. I could go on but I'm sure you get the idea.