How do you have a Steam library? You said you don't even own a computer. You only own a phone. To quote you when confronted about this: " *shrug* ".
No, a person won't be able to play his full Steam library, not at at first, but that definitely looks like it is Microsoft's ultimate plan for the Xbox. They can't control other developers, so they're beginning with first party titles they develop themselves. Second party will surely follow. Third party is always the toughest. Sony will always be willing to shell out some billions for exclusive titles, but that won't stop all the independent developers out there from gladly jumping on board the Xbox platform, too, so long as Microsoft gets out of the way and lets them. The only reason indie developers don't have a wider console presence is because they can't afford to "buy in" to these console markets, so they have to cut revenue-sharing deals. Microsoft isn't making money of hardware sales, but this is where they want to go. I expect them to more aggressively pursue these titles.
Gematsu is nonpareil for surveying the exclusive landscape because of its incredible filters:
http://gematsu.com/exclusives/xbox-one/
The real sign that Microsoft has shifted fully would be if they released an official first-party keyboard and mouse as an accessory (as for certain games) on the Xbox One. For now they're still maintaining a slight separation, but it almost feels like they're doing that out of a sense of propriety to the status quo and gamer sensitivities than it is because they are hesitant about their path forward.
Why Microsoft didn’t turn Xbox One X into a Windows 10 gaming PC