What if I told you

But if PlayStation has an exclusive contract with whichever game, and then that game can only be produced on play station, PlayStation will benefit more because of someone wants.to play they have to drop 500 dollars on the console. So it's a matter of who supports what game first and if they're desperate for production. If Xbox did support this game in the beginning, but play station did (and saw the potential) it's the beginning of everyone having one of each console ya know? Like when games are just coming out they need to make money. And they'll take what they can get, contracts and all

Will it be available at a later date for other consoles?

It costs more money to port games, and how big is your demographic of people who want to play it on XB1? It becomes a problem of how much money it would take to patch and maintain it on two platforms, who will likely have different bugs and glitches, and different problems within their own infrastructure. part of the reason why Destiny was locked up as a PS4 exclusive is because Sony was willing to foot the bill and responsibility of running the online servers, Xbox can pay for it with their subscription fee, but PC players don't have any service that they pay for monthly that would be willing to host the servers and maintain them to a workable condition.