Then why even release new hardware, just keep the 360 going forever I'm sure everyone will be happy since it's all about the games and power doesn't matter.
Now, when people say games matter the most, they aren't saying graphics don't matter at all. Visuals are a big deal, but for all the controversy surrounding it, argument could be made that it's simply overrated in a era where games are in a uncanny valley of realism. Everything looks marvelous and it's not like the days when we ditched the harsh polygonal looking visuals for stuff that looks so much more natural and life like. Everything looks amazing and the argument over 1080p and 60 FPS just comes across as nitpicking to those who don't see that as the no. 1 reason to buy a new console.
1) Disc space. This was a common complaint and made developing for the 360 potentially more expensive since so many devs had to resort to multiple discs.
2) The 360 simply doesn't have the built-in recording features and it seems like that's become pretty popular on both the X1 and PS4. People love capturing their gameplay in the easiest fashion. As far as I know, this wasn't capable unless the game had a built-in theater of some kind like Halo or CoD. Not sure if it's possible to add it on the 360 with updates or not, but this has been a pretty welcomed feature.
3) It might not matter to you, but kinect did receive a nice boost in performance. Hardly perfect, but it's reputation is so much better these days than it was in the past. Whether that translates into game sales remains to be seen with stuff like Kinect Sports Rivals and Disney Fantasia, but people enjoyed navigating the OS with kinect, using the associated features, and increased overall accuracy of kinect. Still not perfect, but it's obviously been improved upon.
4) Potentially, cloud stuff. Sony and MS are promising big things from it and if they even get half of it right, then it could prove to be a big deal for gaming's future and how products are bought/sold, perhaps even rented.
5) Let's be honest, when everyone else comes out with new hardware, then it's time to push out something new as well. MS could've waited a year perhaps, but that's a risk in terms of losing market share. Sony's popularity hasn't dwindled down enough where giving them a big head start would be considered wise.