So, were it is and how many machines do they have? What industry are they from?
At my country, the biggest one, have allmost 500 CNC´s working 27X7...automobile industry. I know that other factorys from the same group have a lot of CNC machines also, so, maybe not even close from the biggest that can exist in the world...
Bigger the firm, greater the need, higher the probability they diversify across national and continental boundaries for a great many very good reasons. Exposure to natural disasters, national grid failures, transport network disruptions, labour strife, political risk, economic shifts...
We (Business OPERATIONS do-er-bee guru's, as opposed to Business ADMINISTRATION scorekeepers) do, actually, study this stuff and apply some seriously gnarly mathematics to it in learning to plan factory locations, their logistics networks and their labour pools.
My point?
If you DO find a Mexican or Chinese factory even
as large as yours - never mind larger?
Those who put that many "eggs" into one vulnerable basket will be among the LESS wise, not among the MORE wise.
The best-managed "Just In Time" plan in the world goes seriously pear-shaped when a blizzard, hurricane, or general strike pays a visit to a primary facility or its materiel "food" supply. Geopolitical shifts tilt the reason for its being. Those can last "forever" as far as the viability of a single plant or campus of them is concerned.
Recent examples? Auto making and even BEER making (Carlsberg's "Baltica" brewery) for the Russian market. Big change. Big shutdowns. Yet OTHER plants making auto's or beer never missed a beat. By the time normalcy returns, such plants can be useless. If even still intact, they've become obsolete.
Mostly, they are not "mothballed". They are sold-off fast and cheap, lest they be simply looted.
More risk than gain to over-concentrate.