Not arguing for either side here, just saying digital goods can be a bit more complicated than you're making them out to be.
First sale doctrine made sense when part of the cost of an item was the physical product itself, but with digital products, there's a near-zero production/distribution cost, so you're really only paying for the right to consume the media (book, movie, game, music, etc)
So in that case, what exactly are you reselling at that point?