This looks to me like a chart showing strong year-on-year tablet sales growth for Apple in China. And generally when a company is selling high margin products at rising volumes we consider that a good thing. Instead this is being reported by IDC and the media in terms like "IPad’s China Market Share Plunges as Domestic Tablet Makers Gain."
Apple's market share in China really did fall a lot, but sales growth was strong. This is the kind of problem a company can easily live with. Smile about, even. China is a huge country that's still very poor. You look at this and you see that in China the market for cheap tablets is bigger than the market for expensive tablets. But despite that, sales of iPads are rising because Chinese consumers who have money in their pockets seem to prefer the iPad to its cheaper rivals. So Apple's China business and median Chinese incomes can grow over time and everyone's happy.
Since Apple is the king of the hill people keep looking for signs of its imminent fall. But so far, there's really no problem with their business strategy. Or, rather, the problem with their business plan isn't that it's not working it's that it's incredibly boring. The Tim Cook Apple Concept is to make really high profits and use those profits to finance dividends and share buybacks! That's the difference between a CEO with an MBA from Duke and a CEO who audited a calligraphy class at Reed after dropping out. It is boring and uncreative. It would be more fun if Apple was building a secret robot army or pursuing a merger with Tesla or doubling wages at its factories or slashing prices by 25% or doing almost anything else other than paying dividends and doing share buybacks. But they do teach you in business school that you're supposed to create value for the shareholders, and so Apple's management is trying. I think that's a slightly silly thing for highly talented people to be doing with their lives and observers are rightly impatient with it. But there really isn't any sign of impending doom.