The majority of playstation owners would not buy it, would not enjoy it's mechanics, and/or return it soon after purchase. What would possess a company to make a financially horrible decision? Every friend of mine I had growing up who owned a playstation (2 and/or 3), that I got to play Halo with me, hated it.
On top of that, a CONSOLE exclusive is not the same as exclusive content. Not even remotely similar.