I am not the OP but I have (many) hours in Factorio and I think what they might be talking about is things like how it’s not apparent at the start just how much copper infrastructure you will need by the time you get to rockets and space platforms because the early recipes are iron-heavy. Or how important green circuit scaling will become. Or how much oil cracking might change your layout.

If you know what’s coming you make different choices in how you build that heads off a fair bit of refactoring.