It's just too many systems for me personally. At one point I had NES, SNES, Atari Jaguar, PS1, Dreamcast, PS2, Xbox, Wii, and Xbox 360 games and I felt like I had more games than I wanted or could ever play, even though I tried to stick with the good games. I ended up selling off all NES, most SNES (and getting a SD2SNES cart instead because I do love Super Nintendo), PS1, Dreamcast, and PS2. I like having less systems that I'm moderately interested in and focusing on the stuff I really love.
Plus, the PS3/PS4 seem kind of similar to the Xbox360/X1 and I've never seen any exclusives that made me want to pick up a system just to play Sony. My son likes the Little Big Planet demo at Gamestop, but I just bought him a Wii U and a dozen games so I'm not getting a new system for a game about a ball of yarn.
Oh, and Sony sucks after what they did to Razellionhart.