Well Michael Bay was probably right, Microsoft wanted iHD utilised, and were probably a bit miffed that the Blu-Ray group didn't take it.
Common misconception that people have that Blu-Ray is a solely Sony medium, when its not. Sony happened to be ONE of the many partners in the format.
Now that Blu-Ray is the winner, it stands to reason that sales of the PS3 will go up as its currently the cheapest way to get Blu-Ray and a decent console.
Only thing that will hamper that is Microsoft significantly dropping the price of the 360 and releasing a dirt cheap external Blu-Ray drive, but then that would then be Microsoft admitting that there is a digital format that they don't have a stranglehold on.