China(up to now, now with tariffs stuff... who knows) has been exceptional in that they produced IoT devices for many use cases at very reasonnable prices. Want a water leak detector that's zigbee connected? that's only 5 bucks. if I want to buy one from a "western" company(still produced in china) it instantly gets marketed to a premium market and costs 10x or 20x more.
They have no incentive to make their products work in pure local when companies like Tuya provide SDKs, chips, and frameworks at a low price and easy entry barrier. But of course that locks into their ecosystem.
It's possible that a company making an open toolkit with easy integration for esp32/etc could gain enough traction to get many devices to use that, but at this point it's unlikely.
As for HA... I love it and run it locally, but it's not for the faint of heart. And spending dozens of hours modifying devices and configuration to get everything running is a priviledge few have the skills, time and knowledge to do.
As always... this is a case of "the only incentive is money and hence the system will lock itself".
Wouldn't it be great if the EU could force these companies to surrender local control?