Well, if you have a strategy that has detailed turn by turn instructions for the first several 100 turns, and where it's optimized enough that you need to follow it to the letter (and not have too much bad luck with random events) to not run out of cash, it gets kinda tricky I guess. Or boring if you don't understand what you're doing and don't see the point of fiddling with building X + Y buildings where X and Y is changing every few turns :D

Also I think sometimes people are just too stubborn or lazy or bored to follow a strictly made up strat.