I think it will be a losing strategy if Sony follows MS with the 3rd party approach. Sony are in a very different position to Xbox, where Xbox does not have a viable console only business, Sony does. For Xbox grabbing revenue from PC players and competing platforms makes sense, as they were not getting that revenue regardless. For Sony it will be an outright loss, if players shift away from their platform as a whole and instead are only purchasing one or two blockbuster games on other platforms from Sony.
Sony also does not have the games lineup that Xbox has where success is primarily driven by number of active players such as COD/Diablo etc.