"rock band countdown"

[FlashGordon]

"with the exception of a few things on "the white album" and "abbey
road", I don't think the beatles are considered a "hard rock" outfit.
the stones are "rock" no matter where you put them, the
beatles have been considered more a "pop" band than "rock"

It's interesting that bands that lean toward pop, folk or other softer
sounds aren't always considered real rock these days.  I used to think
they were just subgenres like hard-rock, folk-rock, pop-rock, etc.,
but maybe people don't classify them that any more?  What made the
difference?  The punk sound?  Alternative?