Apparently the studio reached out to Sony before Titanfall was exclusive to Xbox One, Xbox 360, and PC to iron out a PlayStation 4 version, but the company wasn't ready to share PS4's specs with Respawn. Instead, Sony suggested Respawn bring the title to Vita, which sadly never happened.
Titanfall has proven to be quite the commercial success for Electronic Arts thus far. It will be interesting to see what platforms the inevitable sequel comes to in a few year's time. Would you play a handheld version?