You're acting like MS had no other choice but to bust in mid-project, while in reality these studios were focus mainly on one project at a time.
Again, they acquired PlayGround and Undead Labs between projects, so it clearly wasn't impossible.
Is it that hard to believe that a big announced project with known release date might need more hands on deck than an unannounced side project?
You have a warped reasoning that does not apply when it comes to mergers and acquisitions. You do not wait for a company to complete what they are doing before you acquire them, and I do not know where this utopian view you have comes from.
EA acquired BioWare at a time when they were ramping up to release Mass Effect.
Microsoft bought Bungie who had been working on a third person shooter called Halo: Combat Evolved. The game had been revealed in 1999, and later became the first person shooter we know it to be.
Rare was bought just as they were releasing Starfox Adventures on the GameCube, and they then went on to release a good amount of games on the GameBoy Advance.
Playground, Ninja Theory, InXile, Compulsion, Double Fine, Obsidian all follow this model where Microsoft will buying a developer regardless of what they are working on.
If they are working on something, get it out of the way and build. If they do not have anything on the horizon, even better. This thinking that ongoing projects is something that will deter publishers/platform holders from making acquisitions. And these were not the hostile takeover you saw when EA got BioWare and Pandemic.
Each of those developers wanted stability, to make games, have freedom without having to worry about the money side of things.
