The world of reverse engineering is indeed a strange one. It’s a landscape of claims and counter claims. Fantastic stories and skeptical analysis. The characters are legendary and the truth elusive.
One constant is the proposition that DARPA may be the agency responsible for any advances in the technology. While DARPA does have a hand in a lot of advances in technology, they only push projects forward – they don’t do the work.
As noted by Nicholas Evans in Military Gadgets:
“…airplane, tank, radar, jet engine, helicopter, electronic computer, stealth technology and internet, none of these that transformed warfare in the 20 and 21st century owed their initial development to the military but were accelerated into service by DARPA.”
And they work with a limited budget.
A quick look at the DOD fiscal 2020 budget report shows the research budget for DARPA at a little less than 3.5 billion per year. NASA had a 22.6 billion per year operating budget of which the shuttle takes a third.