Thanks for emphasizing what I've been saying for years now; yet the luddites never get to understand it.
It's OBVIOUS that Blu-Ray will be selling more in the future; but it's even more obvious that the adoption rate is simply not there for 99% of the people. The gains ARE marginal and way LOWER compared to the migration VHS-DVD.
Sure, if I am a new consumer buying a first-rate big screen TV and a disc player, I will probably get one with BR features (yes, I prefer BR to the stupidly illogical acronym BD)...does this mean BR is already mainstream? Absolutely not.
Just check mature market channels such as Best Buy in the US and you'll see that DVD FAR outsells BR by a large margin. Add to that the new streaming/download options you mentioned above, the much more stringent DRM in BR, plus increasingly ubiquitous broadband access (heck, I have 20Mbps for 40 bucks here in Switzerland), and you'll see that BR is a moribund technology just like videodisc, Minidisc and Betamax, no matter how much greedy manufacturers and studios try to push it.
The main reasons that BD is not being bought at the same rate that DVD is is because people have their DVD players that replaced their VHS players, DVD players can be bought for under $30 now whereas BD players cost between $100 and $300 (more with advanced options), and BD movies cost more than DVD movies for now.