The fact that Sony, who Microsoft insists is absolutely obliterating them in the gaming space, doesn't have the money to enact these sorts of massive mega-mergers seems telling that this kind of a deal is not just a natural part of the market. Rather, Microsoft is just leverating their wealth from their other businesses to armstrong the market.
The only recent significant studio acquisitions I can think of already had a long history of making PS exclusives (e.g., Insomniac).