I wonder if this has anything to do with the Halo situation. Correct me if I'm wrong but Bungie didn't want to keep making Halo games but MS kept wanting them to so Bungie dipped which was a good thing that Bungie wasn't bought by MS.
So if MS buys Playground Games then they'd probably want to ensure they'll make Forza games forever. It's fine if Playground Games only wants to make only Forza games, but if down the road they want to try to make something different then they could be screwed.
They made 343 to just make Halo. Coalition to just make Gears. And I'm guessing this just to make Forza.
It would be interesting to find out if Playground was pulling a Bungie though. Would explain why they have to buy the studio to get the games they have already been getting.
I can definitely see MS's point of view for wanting to secure Forza, but I think we all felt they're on great terms that there'd be no reason they wouldn't continue making that game while pursuing other games.
We see how great of a relationship Insomniac is with Sony making great games while still able to expand and make Sunset Overdrive for XB1.
I guess if MS just wants to start owning a bunch of developers for the sake of ensuring 1st party games keeps getting pushed out for their future console then I guess this would be a step in the right direction.