Because there is tremendous risk of having data located in China. This is not the case with Bitcoin. If you put your SOTA AI/ML project there, your IP will be stolen, guaranteed. If you put your Bitcoin mining there, your only risk is the hardware.
They could do the same for ML. Sell the trained models.
Either by giving them to the customer (Like Tesla will put them into cars) or by letting the customer interact with them via the internet (SaaS).
Either way - if the production of the models is most efficient in China, then we should see them being made in China.