Amazon's market share in clothing sales has reached 16.2%, leaving Walmart behind.Amazon's growth is driven by gaining a larger share of discretionary spending, while Walmart's growth remains tied to essential goods.Amazon is making inroads into grocery sales, gradually eroding Walmart's dominance in that category.Amazon's focus on eCommerce, accounting for 86% of its sales, contrasts with Walmart's reliance on brick-and-mortar stores.