Re: Family Sharing NOT a demo mode.
The Xbox One isn't scheduled to come out for another five months. Given the information to get out to the public, a wise PR strategy would be to front-load the "bad" news (DRM, used games, etc) and back-load the "good" news (family sharing, etc). Bad news is often quickly forgotten when new information comes out. You want as much positive press as possible when it's closer to launch. It would make perfect sense for them to hold off on the best news until later in the summer to build hype in the run up to launch.
But this is all moot now, since the reactions to the "bad" news overwhelmed what Microsoft thought they could win back with the "good" news.