You are right that the sentence preceding the TDD article is logically wrong. I have an excuse ;): I had a longer section and quote about it, then just before releasing decided to put a condensed version to the additional notes without too much thought. I will fix it.
I use the terms ‘economic’ and ‘Lean’ in a looser sense than the one you are describing. It’s clear what is meant in the context of the article. Plus, ‘economic’ conveys the redistribution message better than efficient which could also mean doing less altogether.