Doesn't the physical size of your island also limit the scale? Sure, you can literally move mountains, but there's still a finite amount of material.
That is true, but I am not even sure you can cover it all with factory before you computer melts down (and the FPS goes to single-digits). We need to invest a lot more work to optimizations before making larger maps.
You can actually increase the ocean size in settings, making way more space if you decide to move mountains and make new space by landfilling oceans.
Another question over here:
Did you fallow a sociotechnical approach? What school if any?
What about the economics and political things I can found there? Did you think about how this game could work as capitalism? Socialism? Cooperative factory? Having an union among the workers? Having a legislation about protecting industries of something?
What about events like the current container crisis? Or the lack of labor?
Unfortunately we haven't tapped into these topics. We used to have a mechanic based on worker skill level, universities, etc, but that was just not working well for us. The game is already quite hard and we didn't want to add more layers of complexity.
However, we are hoping to polish our modding APIs and allow players to add more layers to the simulation like what you described :)
First, you need people to man your machines and vehicles. You need to first get your workers somewhere (takes time) and also take care of them (food, water, trash, etc). If you scale too fast, you might run out of food and people will starve.
Another aspect is maintenance. Unlike in Factorio, you cannot just spam buildings to scale, because you need to spend materials to maintain your buildings. If you scale too fast, your things will start breaking down (later you can recycle spend products in maintenance to recoup the costs).
Finally, there are a many potential dependency "traps". Scaling too fast and ran out of coal => no steam => steam turbines shut down => no electricity => you built backup diesel generators, fine => now they drained all diesel reserves, oops => trucks cannot deliver food => starvation.
There are many ways how to prevent such death spirals, but my point is that in Factorio (or similar sim games), you cannot loose by scaling too fast. But in COI will. :)
PS: There is air/water pollution too! People will get sick and may die.