You can not say that the One is dead until you wait what happens when the Master Chief collection and the new Halo game will do to it. Heck, there are plenty of other exclusives on the way too. But Halo is the most important one. It invented XBL, fuck, online console FPS as a whole. Halo 2 was the most popular game on the original Xbox. On the 360, Halo 3 had millions of users online in it's first years, it was on par or above Modern Warfare. It spawned a competitive gaming scene. We had Halo pros on fucking Dr. Pepper cans, a car company sponsoring tournaments, Halo was on American television (USA network, ESPN 2), Astro is still supporting the scene... the list goes on. There was so much hype around Halo back then. At that time, almost every high schooler and college student in the US played Halo 1-3 at some point of his life.
https://www.youtube.com/watch?v=y7Q-m2Ki63Q Little hype video to give you a better picture about what I mean.
But then Halo Reach and Halo 4 happened, bending the successfull Halo-formula more towards Call of Duty. The XBox system seller was not unique anymore. Less and less people gave a shit.
So we have this one game series that had a big impact on many gamers lives. The game series that was the only reason for many people to buy an Xbox console.
Then the XBox One came out and we had next to nothing game-wise. Especially no Halo.
But a few months ago they announced the Master Chief collection. People not interested in competitive play may not give a shit about this, but it is a dream coming true for every Halo fan out there. Halo 1, for the first time, can be played online. Halo 2 is back online. Resolution and FPS upgrades, dedicated servers, Halo 2 anniversary being pretty close to the original, Halo 5 Guardians said to be focused on Arena FPS and getting a Beta months before the offical release so that the feedback actually can be used (Fuck you Bungie!)... it's an awesome time to be a Halo fan.
I don't know if one game series can make the Xbox One the most successfull console of the current generation, especially in these times. But Halo definetily can get Microsoft plenty of more sales. We will have to wait to see it's impact.
TL;DR: No it is not dead because Halo.
Also @ OP: Saying a system is dead after one fucking year is quite dumb. As long as one Xbox One user is online, the system is pretty much alive. Someone bigger/more popular being around does not make you insignificant. Sorry but I am pretty convinced that you are trolling.