Pop music has always been, to those who love it, to some degree tribal or factional; fans like to carve out their own space. If you like X you can’t like Y. Punk and post-punk sharpened the divisions. I couldn’t stand Nick Hornby’s High Fidelity for a number of reasons, but it wasn’t helped by its older-brother’s snotty dismissal of pretty much everything that came after 1977, unless it was the latest record by some dinosaur which punk’s meteorite had somehow failed to wipe out.