I only mention altruism because there are at least some members here who seem to think that is the driving force for Spencer's actions. Again, baffeling.
I would hope that few if any members think any of these companies or executives are acting out of any kind of charity.
Their primary responsibility is to their shareholders. Phil Spencer's job is to try and maximize the Xbox division's contribution to Microsoft's bottom line and to their share price. Period.
This is the same with executives at Sony and Nintendo. Their job is to make money for their investors. Where people like Phil, it's because he seems to believe that the gaming side of Xbox is something worth focusing on as opposed to Mattrick who thought the entertainment and casual games (Kinect) was how you got there. That's really the long and short of it.
His policies are still going to focus on trying to increase the market share and profitability of Xbox. The Tomb Raider deal is on that spectrum. He wants people to buy an Xbox One and coercion via exclusives is how that is typically done. The outcry is real, if sometimes a little disingenuous (I think trying to say well, buying exclusivity is okay in X instance, but not in Y instance, is a little bit of hair splitting.)...but Phil, nor any person in his position, is going to care past the point where you buy their box because of what you can play on it.
Altruism and business rarely go together.