And "somehow" is the operative word. And it would need to happen quickly - within a day, ideally - not weeks or months. But it's not just Foxcon. It's also all the component suppliers who make parts that go into each phone. How fast can they ramp up production? What if there's a display shortage from their display vendor, just as one example? And nobody wants to sit on idle excess parts inventory.
And then then there's all the infrastructure needed to get phones in customers' hands. And that's worldwide. Predicting that accurately is tough. As is ramping up production, demanding Foxocon and all of its component suppliers turning on a dime instantaneously with excess capacity and materials that might not be available.
"So people are switching back to the iPhone because they don't want to deal with Samsung right now."
That's true. But the good news is that's not a huge number. From recall data, of the 2.5 million Note 7 phones sold during the two weeks before the recall, 1 million went to US customers. Not a very large number over a two week period. From a survey, 26% of those will take the recall money instead of a replacement Note 7 and purchase an iPhone. But there is also the lost goodwill from potential Note 7 purchasers who going forward will try an iPhone. Have no idea what that number is. I guess that would be some smallish percentage of the expected Note 7 daily sales.
Disclaimer: A lot of handwaving up above. But it should give a rough idea about what's involved.