I mean with starting a relationship with MS, it's not all money, I remember SE's president saying in an interview that he had to give out a serious internal warning to his developers that they could no longer just do what they wanted, and could no longer ignore 360 and PC, as they only wanted to continue doing PlayStation brand development.
It seems a decision borne of both analizing the market correctly, but also that there was something there between SE and Sony. I mean, Final Fantasy is arguably the franchise that made PlayStation what it is today, why would SE not know Sony's plans?