Not even remotely close. Amazon's total retail shipping volume represents about 5%-6% of UPS by itself. Amazon's total shipping costs annually are equal to about 9% of the revenue UPS does currently. You're dramatically underestimating how big UPS + Fedex + USPS are. Those three deal with shipping for businesses and consumers representing $40+ trillion in global economic activity, and of course have a huge share of the US $18 trillion economy. Amazon is still just a large drop in that vast shipping ocean.