Tech Trees and Information

A lot of computer games have some form of tech tree. One of my earliest exposures to something like that was in a 1980 board game called Civilization. 

The Wikipedia page linked above doesn't seem to cover the ship mechanic. You could build ships and they could travel four spaces, if I recall correctly.

If you had a primitive civilization, they had to hug the coastline. If you held cloth cards, you could travel five spaces. If you had Astronomy, they could cross the middle of the Mediterranean instead of hugging the coastline.

I believe cloth plus Astronomy meant you could zip across the Mediterranean and back in one turn. But if you only had one or the other, astronomy was generally more valuable but itself than cloth.

The idea behind my phrase butterfly economy is kind of like having Astronomy in the 1980 board game Civilization. It's an injection of information that lets you do more with less physical material.