This is true, but it's only as sticky as how long it takes to place the equipment and to train people in the next place.
> I think your list of a-f applies to things like sewing shoes
It wasn't really all that long ago when China could only manufacture things like shoes and was considered to be basically a third world country. The only special conditions that China had that made it the next Akihabara was access to a cheap and reasonably well educated labor pool (and one could argue a government that had the political will to push for rapid economic development pushed forward by Deng Xiaoping style reform).
Every other thing that's happened, happened after that. Every nut, bolt, high temperature vacuum sealer...every special soldering skill and QA plant, every automated CAD driven metal milling machine. All of it came to a place that made cheap shoes.
> Walking down the street in Shenzhen you see a vast array of all sorts of components,
During the 80s you could walk around Akihabara in Tokyo or maybe even Ximending in Taipei and see the same thing. In the 90s it was Yongsan in Seoul.
There is no special geographic, resource or economic reason why it has to be in China. And we know this because it was previously in other places. Shenzhen is simply the latest stop for global manufacturing.
Foxconn, the symbol of Chinese manufacturing, after all, is Taiwanese.
It's not like the change happened over night, or even that it's entirely completed today. Japan still makes some of the highest-end precision optical components on the planet, video games and robotics. South Korea still dominates in memory and display technologies. Hell, the U.S. still designs some of the best consumer electronics anywhere.
Someday, people will speak in awe of the tech ecosystem in <insert city in some other country> and talk about the grand 'ol days in Shenzhen...which will be known mostly for drones and pinball machines or something. It may take a decade, but it will happen.