Kaz Hirai has told The Guardian that a PS3 without Blu-ray would not make sense in reality due to slow broadband in many territories meaning that download-only games such as Metal Gear Solid 4 (or 5) would be unworkable.

"Conceptually it may make sense to remove the Blu-ray drive but in reality it doesn't make sense. Also we never want to be in the position where countries without super fast broadband connections are locked out of the Playstation business because the PS3 has gone download only", is Kaz's take on the matter.