I'm talking about tanks and bombs as proportion of the overall economic output. It was higher in USSR than it was in US, or indeed any other country.
And I'm not saying that producing those things is an investment, but rather that Soviets consciously invested into heavy industry to the (rather significant) detriment to the rest of the economy, so as to have manufacturing capacity to produce them.
> The urban centers had something like 10-20% of the population. If the peasants all moved to the cities, there would a) be not enough jobs and b) no food as no one would be producing it.
Well, the peasants wanted to move to the cities because the pay and the overall quality of life there was better. Peasants in kolkhozes were essentially serfs, with the government coming and literally taking the "excess" of their food output away. This could have been solved by, you know, actually paying them properly for that food. But why pay when you don't have to, and would rather spend that money elsewhere - e.g. on industrializing the cities?
One thing to keep in mind here is that Bolsheviks were very much not a peasant party. In the Constituent Assembly (which was directly elected by the population), they were a minority, and the most numerous party was the Socialist Revolutionaries, who actually represented the immediate interests of the peasants. Which is precisely why the Assembly did not rubber-stamp the Bolshevik government, and was forcibly dissolved.
Similarly, in village councils, Bolsheviks rarely had a majority - so they introduced kombeds to override those unruly councils. Also, when the council system was first codified in the 1918 Soviet constitution, the Congress of Soviets (i.e. the ultimate legislative body) had one representative for every 25,000 constituents of urban councils, and one representative for every 125,000 constituents of rural councils - i.e. one factory worker effectively had the same voting power as 5 peasants .
These kinds of things is why there were so many large peasant uprisings in Soviet Russia early on, to the point where they had to use poison gas to effectively suppress some of them.