I'm not sure I follow. We'll never really know how much they are paying for the studios, but both are throwing out the big bucks.
I do think Sony spent more on Insomniac than MS did the likes of Ninja Theory or Double Fine. (Although we do know MS spent millions buying the Psychonauts IP back).
Insomniac feels like a Playground Games level acquisition. Sony's next might be Obsidian level if it's RaD or HouseMarque or even Remedy.
Insomniac is coming off a game that sold 13 plus million in a year. They are in a decidedly different league than any purchase MS has made. Playground is the closest, and I use the term loosely.