Non-capitalist countries also made huge improvements in standards of living, as they industrialized. Again, industrialization is the common factor, not the economic system.
[1] Short, nasty, and brutish.
Not as much as capitalist countries. That's the point.
However, you need something to multiply for there to be any prosperity.
Capitalism for stone-age people would not have resulted in prosperity, wealth, or rising standard of living, just as it did not cause it in industrial age people. Fossil fuels did. Crediting capitalism is putting the cart before the horse.
Just because electrification happened faster in the West then the USSR, doesn't mean that electricity isn't the reason why both societies became more prosperous.
Life was largely shit for most people for most of history, and it wasn't because because people didn't figure out that private ownership of the means of production is more efficient at producing widgets then state-owned means of production.
When 70% of your population is growing just enough food to feed themselves, and the other 30% are banging rocks together to make tools for the first group, you don't have time to think about inventing antibiotics or bitcoin or bicycles.
...and yet here you are making the exact opposite claims that have absolutely no basis in reality and go against any fact, and somehow you show no concern regarding lack of evidence or facts supporting your claims.