As Oleg posted before, these dates were based on the idea of building BoB on the IL2-Engine. While the game was being developed before, work on the new engine was started in 2007, which meant neccessary reworks of most of the stuff already done.
Anyway, I don't know why anybody does preorder a game without seeing any screenshots, videos, previews, reviews, systems specs, release-dates (not release years), etc of the final game?
Even IF it was released then, you'd give you money away months before the release, giving easily away months of interests, this money would bring to your bank-account. Not much, but 50 bucks for 2 years, that's a quite few euros freely given to the reseller.