Over 5.6 million copies seems like an awful lot, especially since 6 erased a lot of the good will fans had for the series.
On a personal note, I look at that poster and experience no joy whatsoever. A generation ago that kind of reaction would be impossible.
I just want my old Resident Evil back. Heck, I'd settle for a game modeled after 5, which at least played well, even if it broke from the series' conventions.