Yup. MS needs to lock down more first party exclusives so it remains a full exclusive instead of porting to PC.
More exclusives are great but that's never been Microsoft's approach. They support and market what they know will sell and put their resources into other areas. They don't like to put all of their eggs in one basket. Sony just throws money at developers and hopes they make a game that sticks. I think Microsoft will be fine as long as they continue to offer the best overall experience, which they have with the Xbox One.