They bought the DoJ once before they can do it again.
MS never was punished for monopolistic behavior in the past; sure you can cite a few nothings that never changed their behavior other than they refined their tactics for the next crime.
MS will simply donate a lot of $ to the GOP again and buy their way out of "jail" again along with some $ for other politicians so they don't squawk as loudly. Worse case, Gates will do some targeted "charity" work in political soft spots; again.