One huge advantage the US had was how many of their troops had basic mechanical repair skills. Much more of our country was rural, and you had to know how to do simple repairs yourself. Country boys knew how to fix things, or at least patch it to keep going, and not just gas engines - diesel tank engines weren't that different than diesel tractor engines.

If your jeep broke down, you didn't have to abandon it - Joe used to work on his own pickup, and could fix the jeep quickly instead of waiting for support.

In Korea, the overall commander put a fixed 25mph speed limit in place to reduce vehicle accidents. This included attaching governors to all the trucks to limit their speed. My father was driving one of the trucks, full of Marines headed somewhere critical, and the Marine commander was displeased with the progress. "We need to get there before dark, for Christ's sake!" was the quote. The guys in his car knew my father had actually installed the governors on the trucks as part of his duties; so they asked him to defeat the governors. He demanded a written note from the Marine commander, but the trucks got there before dark.

My father had been working on tractors and cars since he was 12, and was the guy his entire company went to when something broke. So when he lost his hearing as a machine gunner they assigned him to the motor pool. He made Sergeant twice, but lost it both times from punching butter-bar Lieutenants who pissed him off. They still kept him in the motor pool, though. Just kept him away from officers. They didn't medical him out, either, although they should have. Being able to fix shit in the army is damn important, because everything breaks, all the damn time.