It could also be that unfortunately, brick and mortar stores no longer dedicate significant shelf space for PC games unfortunately. Walk into a Fry's, Best Buy, Target --let alone a GameStop, and the PC games section consist nothing but WOW or Diablo and one offs here and there.
For whatever reason, it's console games that rule the retail marketplace here.
Thankfully, Steam and GOG have brought back PC exclusives back into the fold.