All of these arguments are missing the point. They're attempts at strawman arguments, though I don't believe it was out of malice. Technologist progress is a function mostly of population and time. Both the US and USDR made significant technological progress, so economic system is a less important (still important though!) factor.

The argument is that the modern economic system compared to our grandparents' generation is worse. We have less buying power. We have less publicly funded welfare to act as a safety net. Workers have less bargaining power than times past. Large corporations are taking advantage of consumers and workers at huge rates.

We could have had all of the technological progress we've made PLUS our grandparents' economic situation if our parents didn't fuck everything. That's the argument.