Re: Connect directly to the Internet?
That's more or less Zigbee, an open standard with enrollment, encryption, commands, device profiles, etc that is extensible and cutsomizable.
And to a lesser extent Zwave, as it supports vendors extending new commands and parameters,although its more managed like USB & BlueTooth.
So this exists ,but the big names have avoided it because it a) requires a second radio, adding costs b) requires following someone else's spec, and c) they can't control the products.
Going to a wifi-based spec (aka Zigbee over IP) means these companies don't need that second radio. It means the bulk of validation becomes standardized, which can lower certification costs and hassles (which I'm sure is contributing to Homekit's woes), and they can still add an extra chunk of code that operates at the TCPIP layer to do non-automation functionality (i.e. voice assistant-y audio) as well as potentially being a "gatekeeper" so that HomeKit won't bother controlling anything that doesn't also have an iHome authenticator key.