Sure but what would they have to steal from the Soviets?! I mean the West had A/C, cars, color TV, computers and so on while USSR was struggling to feed its people. Reminds me of the old Soviet joke brilliantly included in the Chernobyl series:
"What’s as big as a house, burns 20 liters of fuel every hour, puts out a shit-load of smoke and noise, and cuts an apple into three pieces?
A Soviet machine made to cut apples into four pieces."
Soviets have had a very strong educational system, and a large number of scientists and engineers. Even mathematics, on which all the other science rests, was actively developed by the Soviet. E.g. Andrey Nikolaevich Kolmogorov basically invented the modern probability theory.
To claim that their engineers have done nothing but wait for spies to come back with US knowledge is a little absurd.
How much of the technology in your car was developed by the Soviets? How about the last airliner you flew on? How about your computer? How about your phone? How about your TV? How about agriculture?
Yes, the techonology created by free market countries. The evidence abounds. Your computer, for example.
> As a counterexample, I'd like to point out the Soviet space program.
Yes, the Soviets did have some technological successes. But look around you. How much in your home is communist developed technology? I can't think of any in mine.