Speaking for myself -- a fan since 1981 who bought The Number of the Beast on cassette when he was 12 -- I have bought the four albums including/since Brave New World. Guessing I'm not alone either.
I love the classic maiden just as much as the modern maiden.
Edit: I do like the classic maiden a bit more, but to be sure, TFF is as enjoyable to me as anything they've done.
Not alone, but obviously, a lot of fans did not. If you compare the number of people who go to their shows with their album sales, it seems that there's a lot of people who will see them live that didn't (at least in 2000) care much for their newer material.