I wouldn't say I ever bought a console for only one game in specific. Like when I bought a PS3 for FF Versus XIII that was a big factor in the purchase of said PS3 but I knew there were other games I wanted as well. But if H1Z1 is all that interests you in the potential purchase of a PS4 then I personally wouldn't even consider the console for just one game, no matter how badly I wanted that one game.

Just my two cents though.