Kaizen isn't a perpetual advantage. Just look at what demographics are doing to the Japanese economy and manufacturing base. Korea is the new Japan in many ways, and any honest Japanese manager will willingly tell you as much. Korea came from literally nowhere to catch up to Japan, despite kaizen.

Disruption, rising costs, aging demographics, etc., can easily shift industrial edge from one country or region to another.

I'm not denigrating kaizen, mind you. It's still a valuable principle, and one that will continue to confer many advantages to the Japanese industrial base. But it's not a sufficient advantage in perpetuity.