Yeah Square didn't promise us anything, but they said it would be on the most famous/ popular console, which PS3 was put in parenthesis and I highly doubt that the PS4 will be the most popular gaming system by the time KH3 comes out since both things were just announced, but hey, you never know. I don't have a PS3, I prefer my PS2 , but that's my opinion.
On that, I know what you mean, and I can agree with some of it, but I myself, am not old enough for a job, and my parents can't afford a PS4. Not that everyone is like that, but just saying not everyone on this site is old enough to have a job.