China can SPV mine, which they do already, but it is risky and puts them at a further disadvantage.
Why? They can control the pool abroad.
A pool abroad is a loser. It just adds latency. Also likely easier to block and less reliable. The mining gear itself is pretty dumb. It wants to connect to some reliable (pool) address (or small set of pools) at low latency. That's why they have pools in China at all.