There are so many members of BDA that i don't think Microsoft would care that one of them was Sony.
They are not all Japanese companies and they are not all linked with just technology. If it was just one owner then yeah i could see a case why MS would not want to join but it isn't like that. Pioneer and Microsoft have various partnership deals with one another. They even share patents. Seeing as Pioneer are co creators and close to MS as a company i can't see MS having any problems with using Blu Ray in the next 360.
But i think there will be many way's to play games in the next generation. Direct to drive digital distribution is taking off fast. Streaming technology is getting better as the internet get's faster and more stable. The next batch of consoles will have huge harddrives in my opinion. If you have a minimum of say 1tb in your console it could destroy the need for a disc. Like with Steam you can just download it. And new releases pre-download it before release which get's activated at a certain time. In the UK places that sell physical discs are in deep shit. HMV and Game are basically the last ones standing and they are not in such a great position financially. I would be shocked if companies like MS are not aware of these trends and will plan for it.
As hard drives get bigger and the internet becomes faster it will replace physical cd's over time. The success of steam prooves that.
