Another issue with multi level factories is transporting goods within that factory. Sure, you can install elevators, but factories in the 21st century produce large quantities of goods. Far too many that would make sense to constantly be moving up and down elevators and requiring pump trucks and then forklifts. It's just not really realistic these days in most cases. It worked back in the day, but now industrial production has simply evolved into an entirely different beast.
You also don't find them in city centres anymore because we now know it's noisy and polluting. You wouldn't operate most factories within city centres or near homes.
Getting large numbers of trucks or freight trains to serve industries is also easier in distant areas since they are better served by highways or spur lines.
You also don't find them in city centres anymore because we now know it's noisy and polluting. You wouldn't operate most factories within city centres or near homes.
Getting large numbers of trucks or freight trains to serve industries is also easier in distant areas since they are better served by highways or spur lines.