The Playstation 4 has the crappiest UI this gen arguably of all the major consoles, yet it's far and away the best selling video game platform on the planet.
The Vita's UI is better than the 3DS' too, yet the 3DS is trouncing the Vita's overall sales.
People just want to play games on their game consoles (go figure) with an easy way to access Netflix/Hulu on the side maybe and that's about it.
To be honest I don't think people want to do 1000 different things while sitting in front of their TV. TV time is either relax time or "entertain me" time and that's it. I don't want to check work emails when I'm watching TV or playing games. I don't want to check the weather, Twitter, Facebook, browse web sites, either, and I think most people are the same way.
I want to be able to watch TV (usually live TV like sports), or movies, or play games. That's all. That's all a game console's OS needs to be able to do, on top of having an online shop that's straight forward to browse (all three of Sony/Nintendo/MS already have this) and an online community structure that lets me play games I enjoy online with other players.
There's no magic to it beyond that. MS tried and failed miserably this gen to emphasis the OS too much with all the XBOne extra functionality and "living room hub" nonsense. And they are getting trounced by Sony as a result of that focus, now they're trying to scramble and reposition the XBOne as a game centric box but the damage has already been done.
The television simply is not the iPhone or computer. Even Apple has not been able to turn the AppleTV into anywhere near the success the iPhone/iPad are. People don't want the TV to be ubiquitious multi-use device. The TV is there to provide entertainment. That's it.
