Beatles hatred seems to be endemic among today's thirtysomethings, I always figured it was just a tired baby boomer vs. Gen X thing.
Your observation is interesting because the Beatles' worst decade when it comes to album sales was the 80s, despite an increase after Lennon's death, with 1983 being their absolute worst year--I call it the "Ebony and Ivory" effect. Since then, their album sales have actually increased to the point where they'll probably end up being the best selling act of the 00s, just ahead of Eminem.
