That’s a reach. Global interconnected private enterprise was widespread before both ww1 and ww2. We haven’t had a war between major global powers after ww2 because of MAD and Pax Americana.
But the globalization of our collective economies in 2019 is dramatically higher than it was in 1919.
Also, how was the US able to fund the massive buildup of arms and the Manhattan Project...which ultimately led to Pax Americana and MAD? By taxing the massive wealth generated by private enterprise.
Warfare is down even between nations who wouldn't fall under the definition of MAD (no nuclear weapons programs). How do you explain that if not for the aligned incentives created by a global economy?
The reason people are willing to buy US government debt is because they are confident the US government will be able to pay them back, with interest. Why are people confident in the US government's ability to pay...and where does this money come from? The strength of the growing US economy and the money the government will derive from taxes on this growth.
Or conversely, let's look at what the US government spent that money on: supplying the war machine via US industrial capacity. That industrial capacity wasn't created out of thin air. Take a look at Detroit for example. Absent the existing industrial capacity enabled by the automotive industry, the allies would likely have not won the war.
Both the ability of the US government to deficit spend, and the things they spent that money on, were a direct result of the strength of the US's private enterprise.
If you include the millions who died in various famines as well as those that were executed directly by Stalin, the number of victims of the USSR has been estimated to be anywhere between 6 and 15 million people.
The Soviet Union has to be the worst counterpoint to anybody arguing against private enterprise.