There is a lesson that manufacturing leaders seem determined to learn the hard way: flooding factories with new technology does not improve their performance.

Roger Smith learned it at GM in the 1980s. Elon Musk, for all his other achievements, admitted by tweet to making the same mistake at Tesla last year.

To really improve manufacturing performance, you start with, as Crispin Vincenti-Brown put it, with “what happens when the guy picks up the wrench.” You work with that person to make the work easier, faster, safer, and less prone to deviations and errors. In doing this, you apply, as needed, technology you can afford that operators can work with.

This is hard work but it pays off. It is a key lesson learned from Toyota, TPS, and many companies that implemented it under the “Lean” label. But it’s an eat-your-vegetables message. The lure of a technological shortcut is irresistible.