Citing Destiny as an example, Ryan told CVG that it makes more sense to partner with third parties on console-specific content and bonuses.
gamescom 2014: Sony PlayStation press conference as it happened
"Well, you know, we've got a very large and very powerful network of studios on our own, all of whom are working on games that will be fully exclusive to PlayStation, and we feel that this on top of partnering with third parties where it makes sense [is the way forward].
"I think the partnership we have with Activision on Destiny is a good example of where it makes really good sense for them, it makes good sense for us and it benefits our consumers - when you complement those two things we think that gives us a pretty complete position in the market."
Responding to Microsoft's Rise of the Tomb Raider exclusivity deal with Square Enix, Ryan said that his company already has a strong portfolio of exclusives.
"So do we feel the need to go out and buy outright exclusivity? Probably not," he continued.
"You saw last night [at Sony's gamescom conference] that before the media briefing we showed updated videos of games that we had revealed at E3.
"That's because we wanted to keep the show itself full of new, fresh things. We think that gave us a good, strong, convincing portfolio of exclusive stuff and we're happy with that."
Microsoft announced that Rise of the Tomb Raider would launch in holiday 2015 exclusively for Xbox One and Xbox 360.
However, Microsoft later said that the exclusivity deal "has a duration", leading to speculation that the game will eventually launch on PS4.
Watch a trailer for Rise of the Tomb Raider below: