There might be life in this
That is, if they can get the box makers (Honeywell, appliance makers, security systems makers, some entertainment systems etc) to sign up. Those companies don't stand a chance of coming up with their own UI - or nothing that will be any good, or endure. And faced with products like Alexa and Nest, they would probably welcome somebody else unifying things through a comms hub with a nice UI, in a way that doesn't threaten their core business, but relieves them of the tricky UI software and interlinking aspects.
Personally, I'm still not buying the IoT pitch, so I won't be in the queue here, but Rubin and buddies are smart guys with a track record, and they know that they can't take the big tech companies head on. With product makers worrying that Google and Amazon will shit on them, they might see this as well worth playing ball with.