Firstly this entire debate about Microsoft buying exclusives is entirely conjecture. Sometimes they gasp actually earned the treatment they received. By being a superior development platform. By having a better install base. By having better marketing, and a better release list. Yes developers who have limited time or budget will make a more advantageous choice.
Speaking to the nurturing crap I saw laid out in this thread. I am sorry no manufacturer is a blessed angel, or beneficent overlord. I have read where Sony bought a studio that was circling the drain, and then the next day asked the staff out to the parking lot to fire half of them on the spot. Now I ask you is that nurturing. Bungie wanted desperately to get out from under Microsoft. Earlier this year Microsoft canned a dozen artists at Rare, and Sony has done the same with their own staffs. This is bullshit pure and simple.
Speaking to paying for exclusives be they purchased outright, or merely for a time advantage. Well developers are people to. They have families to feed, and bills that need to be paid. When their company is sold they aren't the ones getting a piece of that action. The reality is when a small developer does better it usually translates to a better wage for the staff. Hell many of them even have profit sharing.
A developer being paid is getting a better deal then a developer being bought. They get to keep their autonomy, and when they do well it is they who are reaping the rewards. They are the ones cashing bigger checks, and the individuals in those companies have greater control over their lives. They are not expendable, and their projects aren't movable.
I root for the little guy making good, and if they can do good by playing manufacturers against one another. Then I say good for them. They are standing tall among giants.