"...Sales of BD players was supposed to surpass DVD players by August according to BD promotion group..."
I hadn't heard that. Link? Sounds way too soon, far more optimistic than anything I've read.
Surely, the price of BD players will decrease. If the cost to the consumer to have a player that plays both (plus CD flavors) is small enough, they'll go for the flexibility (usually). For the B&M, it is easier to make a buck on a higher priced item, so there's a push there, too, even if it's only a slightly higher priced item.
Eventually, a large majority of players sold will be able to play both DVDs & BDs. When? I have no idea. Prices have already dropped much faster than I anticipated. And I've come to own two BD players far sooner than I expected. And I'll own 3, if OPPO ever gets off their butt.
I doubt DVDs will ever disappear, at least in my lifetime. But I do see BDs eventually surpassing DVDs in both dollar and unit sales. They simply offer so much more, soon for so much less additional cost.
Side note: I recently saw CIRQUE DU SOLEIL KOOZA. Great show. As we left, I said to my wife "I wouldn't give $20 for a DVD of this show, but I'd pay $50 for a Blu-ray version." Granted, not everyone would feel that way. But a lot of people that go to that kind of show would.