Not the same. A can of tomato sauce on sale this week has insignificant impact on general commerce. But the price of transportation underlies everything. Amazon can't offer "free" shipping without massive price concessions from the shippers, and the shippers can't offer those concessions without making up for it every place else. Again, investigate this yourself. Price out the undiscounted cost of returning an item on your own dime. That cost is the subsidy which small shippers are indirectly paying to their larger competitor. Not just on prime day, but every day.