Optics manufacturing went world-wide long ago, just like any other sort of manufacturing, from cars to televisions. Every company buys at least some components from another specialized company, whether screws or lenses.
I don't know of a single optics company that makes everything under one roof. Some companies may grind and coat their own lenses, but they don't make the glass itself.
This is true. Whether its optics or airplanes, we'd be hardpressed to find all components manufactured and assembled in a single country. US-assembled jet engines, avionics and airplanes may be branded "made in the USA", but many of their individual components/sub-assemblies are manufactured in countries that would make an American/European product advocate's skin crawl.
Same goes for T-bones and toothpaste. At least some of the materials used in those products (fertilizer, feed, antibiotics, etc. in the case of the steak) are OFTEN (not always) made in countries some folks consider uncouth, unclean, unqualified, unethical, unamerican, etc.
