Zekkyou on 05 June 2014
Titanfall is a bad example. Were it not for MS's deal then TF may never have actually been made. Thanks to TF's sales and that deal Respawn should now have plenty of money for future games, so TF's partial exclusivity benefited us more in the long run that it did negatively impact anyone in the short term.
There are also two sides to your argument that have to be considered. On one hand, yes, going exclusive (or partially) does remove a large chunk of potential sales. On the other hand it gives the developer financial security with that games development, which can allow them to make something more risky (Sunset Overdrive and Heavy Rain being good examples).
