Why Is Selling Single Items So Difficult Now

Amazon has made this entire process so confusing and frustrating that I even wonder if its even worth my time to spring clean my basement with single item sales?

Nearly everything I want to sell requests a letter from the manufacturer. I can get if I was a liquidator with bulk inventory of the same item to clear, but I’m just trying to sell one or two of an item.

Is there a way to do this without dealing with the approval letter stuff?