Clickbait title. There was a story recently that said that all of the devices had flaws with MAC address randomization. There's literally nothing special about the iPhone here.
That just looks like a bullshit justification for having a clickbait title. It's not like this title will make Apple pay any more attention to the issue. All it does is try to elicit pageviews from other people, while simultaneously misleading them (because the title implies it's a problem unique to iPhone 7, and not everybody is going to read the whole article).
This is known behavior: according to the iOS 10 Security white paper [1], "iOS uses randomized Media Access Control (MAC) address when conducting Wi-Fi scans while it isn't associated with a Wi-Fi network... Note that Wi-Fi scans which happen while trying to connect to a preferred Wi-Fi Network aren't randomized".
I haven't put much thought into it, but I wonder why they don't randomize all probe requests...
Also possibly because, if it is associated with a wifi network, then it's already sending packets with its MAC address, so there's not much point in randomizing some of the packets.
Of course the neighbours could always find this out anyway by watching the traffic on your channel as there is never any MAC randomisation involved in talking to a known access point.
They might choose a different MAC for each network, but surely for a given network they use the same one? Many people use MACs for securing access points and a continuously changing MAC would break that.
Your neighbour would be using some sort of correlation to work out the MAC anyway, so all they'll need is that it doesn't change over time for your access point.
Yeah, I would only be a little surprised if it turns out to be feasible to reconstruct 3D shapes to freakish accuracy via wifi signals. Perhaps not anytime soon, though.