'As Chris Taylor puts it, "you can't just build in Moscow and click on Paris." Air units and even certain naval units can traverse the massive Supreme Commander maps quickly, but the biggest guns that you can produce in bulk will have to travel across the land. So the question becomes: how to get them there?'
Er...I thought that, real-life historically speaking, the biggest guns belonged to the battleships, the largest bombs belong to the aircraft, that sea travel was the slowest and that armies have moved across whole continents in just days, weeks and months if on foot? (German Barbarossa campaign, Mao's 'Great March', Soviet counter-attack in late 1941-early 1942).