No, Sony does release quarterly games. Its in form of timed exclusive games. That is how peop;le trust their content. They have some of the biggest timed exclusive on their platform.
This year alome, they have FF16 as timed exclusive with Spiderman 2. Xbox doesnt have that type of timed exclusive.
They need to be bold and do timed exclusive games like x360. After tomb raider, they chickened out and stopped doing it.
It's probably more a numbers game than a case of them chickening out. I assume it's really expensive to compensate publishers for the potential lost sales on PS. When MS was winning the western markets in the 360 days I'm sure inking the exclusivity deals was a lot cheaper. If it costs them more than what they could conceivably make back on their 30% of a third-party game it just wouldn't be sound business.