I think a game like Titanfall with a strong multi- and singleplayer would sell better as with only a strong single- or multiplayer but on both platforms and I don't think that sales of singleplayer games would be so much lower on Xbox if advertised the same (at least not shooter games).
What you say is that Titanfall 1 would be less successful on Playstation because of the lack of the singleplayer and I highly doubt that. Game would sell a little bit better with a singleplayer campaign but that's the case for Xbox as well and sales of the game would be probably still higher on Playstation because of the bigger userbase even without singleplayer.







