I don't like the whole "quantity" argument. End of the day, a lot of what Sony builds that quantity on is low-key or niche stuff. The Japanese games obviously have a strong appeal outside of Japan, but the Japanese market they seemed specifically aimed at has rejected home consoles almost entirely. Those exclusives aren't system sellers, they're not big cash draws (though their financial commitment is probably also much smaller). The indie stuff can often come out as something highly derivative of larger releases, or it can just be a reskinned experience with a little bit of change (see: the swarms of indie platformers and retro-style graphic experiences with little beyond shallow, redundant gameplay).
Halo is the top franchise for the Xbox, that's long been the case. Gears is another, but that's far from where the story ends. Forza is probably second to Halo, not Gears, and Sony really doesn't offer anything to combat that series (Driveclub counters Forza about as well as Killzone counters Halo). Microsoft also backed Ryse, from the Crysis crew, and they backed Insomniac in their post-Ratchet & Clank endeavor that was Sunset Overdrive (really nice game, IMO). Quantum Break is next from Remedy, who handled the original Max Payne titles (before Rockstar made the third) and the well-received Alan Wake. Scalebound's coming from Platinum Games (who seems to work on something exclusive for everyone, haha), and it should fill a decent RPG nice, along with the free-to-play Fable: Legends. I could throw out more names, but I just don't want to keep typing, haha.