I think when someone's buying aftermarket PAF types - especially at the prices Gibson charges - they're looking for something as close to the vintage experience as possible. The original PAFs weren't potted. In fact, wax potting only became popular among rockers when people began playing much louder in the 60s, precisely because the vintage pickups squeal at high volumes.
Today, stage levels in general are much lower than they were from the 60s through the 90s, so more players are happy doing without potting these days. Unpotted humbuckers do often seem to have a little extra air, chime and liveliness.
Of course not all potting is equal; there are different levels of depth ranging from a quick dip to full-on vacuum potting, and different formulas of wax used too. Often mass-production potting is much heavier than that done by boutique winders.
Many feel the muffled tone and dead character of Epiphone's notorious pre-2010 "mudbuckers" was due to them being encased in a solid block of heavy wax underneath their covers.