Should it be necessary to have a PS2, PS3 AND PS4 hooked up all at once to play?

[YukanaSenix]

Every PC is good enough to emulate PS2 Games with HD Settings if you want them to play.
PS3 games will be supported through GaiKai on PS4.
And 2 consoles don't take that much space anyway - PS4 is the only NextGen Console to have and PS3 can stand beside it,let the cables hooked up(HDMI and every HD TV has 3-4 of them) or at least buy a cable switcher thing and store the console somewhere > If you want to play PS3 just hook it up and after you are done put it back.Hooking up 2-3 cables that are there anyway doesn't take much time.

Don't see the problem.