They get what...30-40% of their profits from China?
Here is how it would play out: Tim announces they are leaving China, Apple stock loses 90% of its value overnight, Tim is removed as CEO, new CEO comes in and says they are staying in China, Apple stock recovers 70% of its value.
So ya, even if Apple isn't selected out, Tim certainly would be. You are suggesting actions that a publicly traded company just cannot make. Don't try to outsource such morality to companies, they don't have the ability to act like that and exist at the same time.
So 32% one year ago, 20% today. China is much more sensitive to the iPhone release schedule than other markets, their drop in china has more to do with a meh on the iPhone 8 than anything else.
And Apple is one of the most profitable companies in the world no? They can't spend the money they earn. They could lose 20% and still not be able to spend what they make.