Yeah but it should be hard to get a company to make an exclusive title for a 5 mil customer base, when there's another 7 mil staring at you. Sure you won't sell 1 game per console, but having a larger market is always a good starting point.
I doubt the content offered via PS+ is counted towards the game sales though, and those should be at least 21mil, more like 49mil (50% or 100% membership rate). Anyway, all that number-crunching won't show which console is better (mostly because we've got 2 boxes that are mostly the same). All I'm saying is that as a publisher, I'd probably not make any exclusives (or exclusive DLCs) 10 out of 10 times, unless there was a big wad of money from one side. And if I did make one I'd make it for the console with more sales since the number of potential sales is larger should the game actually be good. That said, I'm still not getting any console until there are games that I desperately want. Both sides are desperately lacking at the moment, and the only game on the horizon that has me drooling is The last guardian. (I don't count Persona 5 and further atelier instances, since it's PS3)