MS doesnt like money, they have money, they have more money than some countries do.Well it's one of the biggest companies in the world for a reason. They see value in this and I doubt a few million subs would make up for the huge loss in sales if it doesn't release on playstation.
What MS likes, and always has liked, is power. You wouldn't throw 70 billion away for games youre already getting if you like money. MS likes power over the consumer, power over partners, and power over competitors. Its their business model, always has been since the early days Windows released and they used tactics to regain a monopoly.
Maybe their goal is to "kill" playstation next gen and get their monopoly but for now they will want the PlayStation sales