Then what about all the cloud enabled spyware? How would that work? (/sarcasm)
Truly though, smart-home stuff runs the whole gamut of privacy and device manufacturer relationships. eg: I have used three different smart/room AC units:
- one requires its own cloud-enabled app for any remote connectivity, no HomeKit integration - one integrates with HomeKit but then leaves an upgrade hint that can only be done through an app with a login - one integrates with HomeKit and pretty much just works
HomeKit then allows me to remotely control via HomePod/AppleTV acting as a router ... of course this is just a different cloud connectivity but with on-premises devices controlling other on-premises devices.
For each manufacturer of smart devices, there is potentially a separate cloud where data is being funneled through. Some devices support multiple upstreams.
I get that Matter should be a way to fix it but the reality feels more like https://xkcd.com/927/
Part of me just wants dumb devices back. Get rid of buttons on a microwave (just give me a knob for time and maybe another knob for power setting.) Remove touchscreens from cars (mine glares at me with certain sun-angles.) Bring back the desktop/computer hutch and phones that don't live in your pocket. However, having the ability to start cooling my bedroom 45 minutes before I arrive home is ... pretty compelling too.
Manufacturers just need to realize that LANs exist and allow their devices to be used with the Internet turned off.
When I'm sitting in my home and I want to turn off the AC unit in the other room or close my garage door, there's no reason I should have to do an IP roundtrip to the manufacturer's server. Both devices are on my LAN. They should just talk to each other. This has been a solved problem for decades.