I agree on the consensus statement; just because a group of "tech experts" and "tech writers" say a phone will get a new Android OS doesn't actually make it happen.
I am not saying that the Moto Z series from 2016 will not receive Android 8 Oreo, I certainly hope they do. I own a Z Force Droid and Z Play Droid, so I would love to see Oreo on them. But...we have already received 2 Android OS updates so if our phones never go beyond 7.1.1 I am OK with that.
I'm pretty sure the article even stated that Moto would not provide an "official" statement to their request. So, until Moto announces that the 2016 Z Series will receive Oreo, everything else is rumor and speculation. As a long time Moto Forum member I can say with 100% certainty that Moto never provides Android OS Update schedules or dates; they just don't. They do have a software update page on their website that lists which phones they "plan on" upgrading to the newest Android OS; key word is plan. I have seen phones listed there and then removed because they couldn't provide the update. When we see the 2016 Moto Z Series listed there, then we will know that Moto plans on updating those phones. As of this morning that page says that Android 7.1.1 is rolling out to all 2016 Z Series phones, or will be soon, so there is nothing even close to official from Moto on their plans for Oreo.
I do think we will see Oreo, but I do not believe we will see it before the end of 2017 since the 2017 phones like the Z2 Force, Z2 Play, Moto G5, etc. will obviously have to receive Oreo before we do. I could be wrong though; but not counting on it just because many tech sites list our phones as "capable of running Oreo". I'm not trying to be a debbie-downer, just don't want others reading this to get excited about Oreo on their 2016 Z Series just because some website says that they "should" receive it.