this is a list( in no perticular order) on why they didnt show the ps4 console
Reason 1. they never finished
they showed the controller but not the console. maybe they never finished the console, they might have the desighn but not the real thing. they most likey have a drawing of it or a dummy console.
Reason 2. they have a secret
with the ps3, they dropped the duelshock controllers, and when it came out, they had the normal duelshock. somthing simalar may happen, maybe the vita games will go into the controller and you play them off the controller. or maybe, theres a hard drive or and sd card in the controller, and you download the games off psn, or steam.
reason 3. SEGAS BACK.
segas last system was the dreamcast, relead in 1999, and dies in 2001. sega decides to be a 3rd party company from now on. but what if, sega and sony merge and make the dreamcast 2, along with the ps4. if that happens, than imagine the games they can make, battle royale 2 would be kick ass. but then again, nintendo might go out of buisness, because they make alot of money off sonic, than, maybe nintendo might be a third party companie, imagine having mario on xbox, it would turn into a shooter. but, also, mario dlc . ok, im getting off topic. but if sega merged with sony, that would be awsome, imagine all yhe sonic? sony merch.
well, thats all i can think of, if you have anymore ideas, tell me in the comments