They should come out again and explain everything down to the tiniest detail. This is useless. You really think they will allow 10 people to play the single player campaign this easy? They won't, for the simple fact that this defeats the whole purpose of implementing DRM and a daily internet authentication.
How does it defeat the purpose of DRM?
The purpose of DRM is to assure that the person who paid for that digital copy of the content is in control and posession of that digital copy of the content.
Unlike the physical media, where only one person can be in possession of the disc at one time, in digital content an exact duplicate can be made an distributed without any changes to or from the original version. Thus, sharing becomes giving. The solution to that is to restrict where digital content will run with DRM. DRM ensures the copyright holder that the person in possession of the content is the person to whom it was licensed.
The Xbox 360 allowed for any player connected to the console to be able to play any downloaded content that was downloaded after the account was added. It wasn't really a feature, because it wasn't intended. It was simply a limitation of the console. With the Xbox One, Microsoft is not only making that a feature, so that all content on the system is available to who ever is logged into the console, but also any content can be shared with up to 10 people. The PS3 had a similar feature but it was restricted to content being available on up to 5 devices. The Xbox One doesn't limit by device.
I can go anywhere, to any console, log in and I have access to my games. I can install and I can play them, and so can anyone else on that console. Likewise, anyone who I've designated a "family" member can access my content from any console anywhere in the world, so long as no one else is using it.
More to the point, it won't hurt sales. My inclusion as a part of someone else's "family" may be temporary and fleeting. So my ability to play the game one day, vs. the next will be up to whoever's family I am in. But with multiplayer games, I'm SOL. I can't play a game with my friend AND play the game myself. I have to buy the game.
So, it won't really be different from how things work today, just you family member you share with won't necessarily live right down the road from you or won't necessarily be a family member. It can be anyone you know. Their right to the game lasts as long as you give them access to it. Once that's gone, you'll need a new "family" to get it from or just buy it yourself.