It's more surprising that Apple ever held the top spot in China. There's like what... 50-100 million people with the disposable income to justify an iPhone, and probably 500+ million people who would go with a local manufacturer?
For reference, in the US in 2023, if you are a family of two and your combined annual income is $19,800.00 you are considered to be above the poverty line. This figure represents income BEFORE taxes are taken out.