Even if there is an official press release from a company made by approved speakers about a product of theirs that has not shipped yet, this is not good enough for us.
You do not need to go far in memory lane to find an example of several authoritative, official claims on unreleased products. Does the XBox One ring a bell?
Microsoft touted that all Xbox One games could be played either locally, or through an online game library on any other Xbox One, and that a user's library could also be shared with up to ten designated "family" members (each game could only be played by one remote player at a time). Users would have been able to trade in games at "participating retailers" at no extra charge, and could also transfer a game directly to any Xbox Live friend on their list for at least 30 days, but only once. However, this system required all games, regardless of whether they were purchased on disc or downloaded, to be tied to the user's Xbox Live account and console. Additionally, the console was to connect to the internet to synchronize the user's library once every 24 hours; if the console was not connected to the internet at this time, access to all games would be disabled until the console was connected again.
http://en.wikipedia.org/wiki/Xbox_One — not pictured: claims about the Kinect being a required part of the XBox One...
We could've started documenting all of the claims surrounding the XBox One just as soon as they were made, but still, those claims were nothing more than that: claims. And sure enough, basically each and every one of those features (or mis-features, if you prefer) were abandoned.
On June 19, 2013, following E3, Microsoft ultimately announced that it would reverse its DRM and game licensing changes for Xbox One so that users could "play, share, lend, and resell [their] games exactly as you do today on Xbox 360." As a result, the disc authentication and internet connection requirements were dropped—however the planned family sharing and disc-free play features were [also] dropped as a result. The console would still require an internet connection to download and install a system software update to enable these changes, but the console would now be otherwise usable without a permanent internet connection. Xbox One chief product officer Marc Whitten stated that the family sharing feature may return in the future, but could not be implemented on launch due to time restraints.
If we did do that, we would've had to regurgitate press release (or worse, the regurgitations thereof from news site) in a pointless game of telephone, while contributing nothing of value to the internet. We also would've had to maintain this information over multiple questions as the product plan changed dramatically several times before release. It's a lot of pain for negligible gain.
Even if your question was about a sensible product from a sensible company with a sensible product plan and a long history of delivering on promises — until something is actually out there, promises are promises. We can't and shouldn't vouch for promises we can't uphold.
Stack Exchange is a network for giving (hopefully) authoritative answers to specific questions. Until a product is actually in our hands, we can't do that. So no, we shouldn't cover unreleased products at all, we shouldn't go developer quote hunting and we shouldn't try to be a poor man's news source.