As I understand it, sound is a pressure wave that propagates through air via (localised) successive compressions and rarefactions of the air. The compressions and rarefactions of the air cause the molecules of air to oscillate about their equilibrium positions. The important point here being that there is no net displacement of air molecules on average, since the air molecules interact with their nearest neighbours during the compressions and rarefactions exerting opposing forces on each other causing their aforementioned oscillations about their equilibrium positions.
Wind, on the other hand, is caused by pressure gradients causing an (on average) net displacement of air from high pressure regions to low pressure ones.
My question is, Why is there no net displacement of air by sound (when it seems that the compressions and rarefactions cause localised pressure gradients), but there is in the case of wind?