[pfdietz]

I promise you there was enormous demand for products to stimulate R&D outside of NASA. Orders of magnitude more. That's why technology was leaping ahead even before NASA existed, and even after NASA's budget shrank. It's also why all that new technology came out of countries without manned space programs.

To make a valid spinoff argument, you have to show that the particular technology would not have come about without NASA. That sort of contrafactual, alt-history argument is really hard to do. It's why alt history has such a bad name in history circles -- you can't really show anything. This means all spinoff claims are dubious. Not only are they presented without the necessary evidence, it's difficult to see how the evidence ever could be acquired.