I am pretty sure that Sony is the largest producer of the 405nm blue-violet laser diodes for blu-ray. So for them it shouldn't be an issue of how many are being produced by other groups just what it costs them to make them themselves.
edit: My biggest reason for this thread is that people seem to think sony can keep making $100 price drops all day long, but I am pretty sure that hurts their bottom line quite a bit. Regardless of wether that $100 just cuts into profits are incurs losses its still $100 dollars of revenue.