So, this is totally pop-evolutionary-psychology, but I think the relevant predisposition is towards hoarding. For 100,000 generations, humans (and our ancestors before then) have had to gather and store food and other supplies to see them through the winter (or other hard times). We are wired to do this because we would have died out if we didn’t.
Building games let you build up your hoard of stuff (whether trains, rails, buildings, tiberium silos, green circuits, …) in a tight feedback loop that repeatedly triggers the “this is my stuff, now I am safe” dopamine response.
This also explains collecting hobbies, and goes some way towards explaining the desire for wealth acquisition in general.