So far, you're the only poster in this thread who is actually from Indonesia, so your post holds the most credibility. Most of the rest of us are just guessing.
With all due respect to our Indonesian board member, just being "from somewhere" doesn't mean you know the inside details of every industry that operates there - especially one that likes to keep information away from prying eyes due to the kind of multi-brand contract manufacturing that goes on. When he states "there is no Giant Instrument factory in Indonesia" he's just plain wrong, and then goes on to compare Fender/Squier, Ibanez and Cort as if they are different factories (rather than different brands who source from the same factories).
The Samick factory, for example, spans something like 4 million square feet over a dozen buildings, has over 3000 employees and builds over 500,000 guitars (they also do 15,000 pianos). It certainly qualifies as a mega-plant, yes? Cort is pretty much the same with its multi building campus, 2,000 employees and reported 1,000,000 guitars per year capacity (no pianos here).
There are other factories of course, like Yamaha (who is actually the #1 largest musical instrument company in the world), but they don't do as much OEM manufacturing for 3rd party brands and wouldn't fall into the "make guitars for everyone" conversation that is being asked about.
There are other factories as well, since there is such a large and music-experienced labor force, but they're not on the same scale.
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