Even setting up a vlan doesn’t work half the time because the mobile apps don’t talk directly with the appliance but phone home to a cloud service. A cloud service that will eventually go offline and leave the appliances orphaned. That’s how GE’s thermostats work.

I think you’re underestimating how impossible a task it is for China to hit a moving target. Even so, their move towards isolationism is at odds with an industry that has the most complex and globally integrated supply chain in existence.