With that said, is that enough for China to care at all? a little? a lot? Meaning, I wouldn't be surprised if China would forgo plenty of jobs from Western companies as their economy matures. Especially if China fully boycotted Apple, I doubt many other US Companies would respond at all
Many of those companies are showing themselves to be spineless right now
Edit: according to Wiki, the US DoD is the largest employer in the world at 2.1M employees.https://en.m.wikipedia.org/wiki/List_of_largest_employers
They'd seize the factories and continue production, at least for the medium term. It makes no sense economically, but it keeps Xi in power.
To Beijing, the factories are valuable for (a) IP and (b) jobs. Apple walking deprives China of (a), but not (b), not in the short term.
In the near-term, expropriation would stave off job losses. (In the cities, amidst highly-skilled workers no less.) In the medium term, production lines could be adapted to make non-bricked products.
Long story short, the threat of massive job losses to China is minimal--Apple has limited leverage over Beijing.
They wouldn't produce iPhones without the chips. They'd just keep running the lines. Apple has limited leverage in threatening to walk away from China.
Either way, 4.8 million people + friends/family, being angry is not a small number. China's population is ~1.3 billion according to CIA world fact book. So it's certainly less than 1% of the population, but not insignificant.