To those saying this game wasn't hyped. This game has been hyped for years before it was even announced. For years people have been wanting Sony to do their own Smash Bros. FOR YEARS.
Personally I think it failed because the cast is just not as unique and they don't have that nestalgia factor that Nintendo has. I mean take any gamer out there, current or retired and they will probably have fond memories of at least a few Nintendo characters. Not so much with Sony's cast.
Then look at uniqueness. I mean having Zelda fight Bowser, or Metroid fight Mewto, ect. These are fights from different worlds. Look at Sony's cast and most of them a person could believe all live in the same world. It doesn't have that huge "wow" factor like Capcom vs. DC. It just feels like a pure Capcom game. At least thats how I feel.