From 2000 to 2008, adjusted for inflation, U.S. consumers have been reducing the amount of money they spend on out of home entertainment. That obviously has implications for providers of video entertainment products, negative for out of home venues but positive for in-home options.
The issue is that Blu-ray, so far, has not grown fast enough to offset declining DVD product purchases. In the technology transition from tape to DVD, the new format seemed to have higher value, boosting sales of physical media and gjrowing the category.
That has not yet happened with the transition to Blu-ray, and an obvious conclusion would be that the successor product to DVDs is not Blu-ray but online delivery.