I don't think you can discount the military applications as a factor. It is not as extreme as in aviation in terms of raw innovation, but without the demand fo

I don't think you can discount the military applications as a factor. It is not as extreme as in aviation in terms of raw innovation, but without the demand for millions of engines for trucks, tanks, jeeps, and all the other machinery of war sparked by the warfare of the first part of the 20th century, the internal combustion engine would not be as ubiquitous as it is today. In thirty years armies went from marching on oats and horseshoes to petrol and Goodyears. Maneuver warfare would have been impossible on electric. And then when the war was over, all that surplus machinery was around, and so were the factories that built it.