Sony and Insomniac are pretty much like childhood friends. Sure Sony tried to trick Insomniac a few times into mariage and Insomniac cheated on Sony because of it with Microsoft. (While it was actually because of the mariage contract in which Sony wants control over everything Insomniac does).
But in the end these two companies really flourish when working together critically and financially. Sunset overdrive was a great game, but Insomniac is audience is on the Playstation platform. Sony has no good reason to buy Insomniac, since they evidently like to work with Sony and the PS audience likes their games, especially Ratchet and Clank.
So Insomniac stay independent and primarily work on Playstation projects (We want new R&C games in the rebooted universe). And Sony should only buy Insomniac if they are in financial trouble.
Please excuse my (probally) poor grammar
