I fully agree, this is the reason I mostly buy Zigbee devices for my smart home. The problem with this rule is that there is already a device on the market that complies with it on paper, but not how you intended: Amazon Echo devices act as Zigbee gateways. While I never tried it, I bet it will not turn on your lights without calling the mothership.
If this rule were to become reality, vendors would just sell your their "mandatory" hubs that handle the calling home part. Smaller vendors would no longer be able to offer their ESP based devices, even though I can easily decloud them via ESPHome etc, if even necessary.
From a purely idealistic PoV, I guess the only way we achieve ownership as you described is if we require by law, with proper enforcement, that reasonable technical people are able to connect to the device on a local interface. But this has so many weasel words already, it would be ineffective and/or lead to regulatory capture ("implement this 600 page, 200$ ISO standard based on XML, don't mind the proprietary extensions ensuring no interop!").
For me, the way to have some degree of ownership of my smart home is doing research before buying to ensure the device either runs on Zigbee, has a local network interface and does not rely on the cloud even for initial configuration or can be flashed with Tasmota or ESPHome with minimal fuzz. I don't see this changing any time soon. It is sad that you need to have the knowledge and time to be able to "own" your smart home, but I at least can help my "tech support circle" where possible to make informed decisions.