While I'd love to see Apple (and others) build more high volume products in North America (in general) and the U.S. (specifically), the problem isn't putting up buildings and filling them with manufacturing equipment, it's staffing those buildings with qualified and skilled workers. That's a major, major problem right now all across the U.S. Despite the nonsensical (and incorrect) yammerings of people like Alexandria Cortez and others, we're actually very close to what is considered to be "full employment" in economic circles. Also, Apple doesn't generally build products in "Apple plants". It contracts with FoxConn, Pegatron Corp. and others for product assembly. Apart from some lower volume products (like the new Mac Pro), Apple generally only does the product design and software development, but relies on these contractors to actually build/supply the products to certain quality standards and volume levels.
As an aside, back when Steve Jobs was first trying to get components and assemblers for the "new to market" iPhone over a decade ago, he did approach some American engineering firms about sourcing and manufacturing the screens, cases and finished units. The American companies reportedly sent in just a few engineers, and they stumbled and struggled with how to manufacture the components and do the assembly, while still having acceptable (profitable) yields. In other words, Apple doesn't pay for your scrap or defects. No company does. So if the contracted demand is 100,000 units, and you have to produce 150,000 to get 100,000 "good" units, you're likely on a path to bankruptcy. The Chinese (FoxConn) sent in hordes of engineers, and they were ready to be up and running while the Americans were still scratching their heads. Also, because of the "labor situation" in China (slaves and little kids work cheap, or so I hear), they were able to source the components and produce the finished units MUCH cheaper than any American contract assembly firm ever could. The exact number escapes me right now, but I think that it was said that if an American (North American) contract company had gotten the original iPhone contract, the average iPhone cost-to-produce would have been somewhere around $5,000? Fact check me on that claimed production cost, but it was certainly waaaay up there.
I don't know that this coronavirus is going to have a real (longer term) effect on the world economy. I'm not a medical person, so I don't know how much of the current scare is real and how much is overblown. For right now, just from what little I've read, more people have died from the "common" flu over the same period of time as we've been hearing about corona. But I really don't know. If there's enough panic (from real or imagined concerns), it will have some effect, at least on the travel and tourism sectors.
