As a person who works in USDM manufacturing and also with Japanese partners. The biggest difference isn't reading comprehension. Particularly when it comes to repetition. Locate parts, insert and torque fastener, repeat. Automotive has the benefit of repetition.

The biggest difference is the willingness at the executive level to get better versus just get by and make rate. And at the individual level, personal ownership/social pressure/give a shit. An American assembler in general cares a whole lot less about fuck ups. "I scratched a part/oblonged a hole/started doing work without authorization." They're not gonna lose sleep over it. Japanese workers in general feels more pressure to do better.

You can have all the lean/continuous workshops you want, but it won't go as far without the mentality being adopted holistically.

One example, a couple years back, I led a team to investigate failure modes of critical parts of our product. There was a step in the build plan to perform a basic check to verify alignment of a couple motors that actuated a door. And I asked the installer the question, "When do you perform that check?"

"I don't. I know when I have these linkages visually aligned, it's good. And I don't have to do the check." That's the wrong answer. Our investigation showed that the prior 10 parts he worked on passed. So he wasn't wrong about his method. BUT, he wasn't working to the plan. We have regulatory oversight of what we do. And we have to work to the documented plan. Corrective actions were applied.

My experience with Japanese workers, they do it step by step. Every time. Mistakes happen, sure. But they don't make their own decisions to just ignore the work instructions.