Discounts roll out well before any new inventory gets stocked. Next year's gear doesn't start shipping out to retailers until after August (some brands end of August).
Discounts are mapped by the manufacturer, not the retailer. For most brands, the first series of discounts is around 20% off. By next season's gear arrival, discounts max out at 40-50% off for the most part. Then close-out prices year after that.