I disagree with one of the basic premises here - that Sony has taken particular risk with their first party lineup.
Sony has released quite a few great games in the last several years. But, I see no more risk-taking than Microsoft or Nintendo, or even some of the big third-party publishers. That's not to say that they're taking no risk. It's just not outside of the norm for the industry. Everybody tries some new stuff, evolves their existing franchises in different ways, and the like. And, everybody relies in large part on their existing big series'. Sony is no different.
The only difference lately is that Sony has cranked out a string of great games. That's good, and they deserve high praise for that. But, let's not pretend it's an act of bravery. They're just doing what the industry has always done, and they've managed to get it right a lot more often than not, recently.