NATO/US have big air forces that would simply put a bunch of its big-$$$ aircraft into the air at high altitude to fire expensive and highly accurate air-to-air missiles and knock down opposing aircraft, then bomb the ground from high altitude to get rid of anti-air installations, and only then fly in close air support.

Stingers are inexpensive comparatively cheap surface-to-air missiles that allow an individual soldier on the ground to pick off an aircraft that happens to fly sufficiently low; it's useless if air superiority is actually being contested or if aircraft are bombing away from high altitude and mainly functions to whittle down the size of the edge the opposing force's air superiority gives in the ground combat.