The right to property is a key fundamental. The communist manifesto as a book describes many ends which I would consider most evil.
1. Arguably this is due to state intervention in the form of gold hoarding and fixed currencies, which meant the financial system was no longer self-righting, and then excacerbated by trade wars.
2. Do you have one single piece of evidence for this?
1. Obviously. But the market doesn't have to be self-righting. Its perfectly possible to construct a timeline with a late 20th century where trade wars, high tarifs, poor application (or no application) of the gold standard and so on and so forth continue. Under such a system the laws of the market capitalism break down and so do market economies.
2. Annual Indices of Manufactuning Production 1913-1938, taking each nations 1913 output as 100 in Paul Kennedy's Rise and Fall of the Great Powers. All subsequent figures also come from those books, although I can probably dig up other books that cite much the same figures.
By 1938 the UK was producing only 118% of its 1913 output. From 1920 untill 1935 its actual production was actually lower.
For the Soviet Union, while manufacturing fell to something like 12% of 1913 rates in 1920 it was back up to 1913 rates by 1926 and by 1938 growth was at 857% of the 1913 figure. Global output by 1938 had almost doubled, at approximately 180% of the 1913 figure.
The German economy performed in a similar way to the UK, a post-war lull, recovering in the late 20s only to crash with the depression, yet from 35-38 its growth rates far exceeded those of the UK and France.
Now you might argue such growth rates hide the fact the UK and France were producing so much more than Germany or the USSR. But this wasn't true. The USSR as a share of world manufacturing from 1929 to 1938 forse from just 5% in 1929 to 11.5% by 1932, 14.1% by 1937 and 17.6% in 1938. The UK meanwhile had hovered at around 9.5%
Germany moved from 11.1% in 1929 through to 13.2% in 1938.
The USSR's agricultural production obviously declined considerably, but its industrial expansion more than made up for it. From 1928 to 1937 Russia's income rose from 24.4 to 96.3 billion rubles. Coal output rose from 35.4 to 128 million tons, steel production from 4 to 17.7 million tons and so and so forth. In total industrial output the Soviet union was probably close to if not surpassing Britain, an astonishing rate of growth given the devestation in 1920.
Now the USA didn't suffer the same problems as the Europeans, but her own economy was badly hit by the depressions in the 1920, the great depression of 1929-30 and the rarely mentioned 1938 depression.
In terms of raw output, the planned economies out performed their free market rivals from 1919-1938. They didn't in the post-WW2 era because the global economy was less prone to collapses and the vast stock of dollars and their related institutions provided something of a keel.