I'm very skeptical that China is the only place Apple can make their products. Sure, Apple doesn't actually "manufacture" anything -- the company outsourced it to Taiwnese CM's like Foxconn, Wistron, and others who have cleary demonstrated that they have no competence, experience, or even desire to build things outside China (see Foxconn's misadventures in Brazil, Wisconsin US). But that shouldnt' be surprising considering that their business model entirely depends on ginormous state subsidies and seemingly unlimited supply of young, unskilled laborers from rural China. Also consider the fact that most critical, high-value components come from not China, but South Korea, Japan, the US (some via TSMC in Taiwan) -- China still makes less than 5% of all chips produced globally (as of 2019 according to US SIA). Of course, they are all assembled/packaged there, but China's contribution to this whole process still accounts for less than 4% of overall value.
I just don't buy the argument that China as the world's electronic supply-chain can't be replaced.