> Someone wanting to build would have basically the same intelligence as a civil engineer today, they would just have a smaller set of materials and techniques.

> Someone wanting to build would have basically the same intelligence as a civil engineer today, they would just have a smaller set of materials and techniques. Not just a smaller set of materials and techniques, but also a smaller amount of time around the requirements needed to just survive - getting food/shelter, etc. Advancements in civilisation makes the overheads to staying alive smaller, so more time and effort can be spent on advancing technologies.