"In short, it looks to me like Sony got the rights to print/alternative media, MS got the sacred TV cow, and Rockstar is doing a little bit of everything because they have no contractual obligations to themselves."
This could be the exact reason Bodhesatva, good post.
Sony do tend not to advertise their first party games very heavily on the TV until at least a week or two after launch though. (Ratchet an Clank Uncharted etc.) So perahps we will see Sony GTAIV ads in a few weeks time, or maybe not at all.