Setting aside that you pulled that number out of your ass to argue against it, if something produces 400X it's purchase cost over it's operational life time, a 2% improvement takes that to 408X it's purchase cost for only a 2X increase in initial outlay, meaning it pays for itself 4 fold.

But very few innovations have that sort of effect on manufacturing cost to start with.

This doesn’t make sense as a reply.

How is your own opinion, on another user’s example number, even relevant enough to be “setting aside” in the first place?