It seems like the easy solution for Bethesda is to not sell physical copies anymore. No one argues about trying to sell the $10,000 dollar seam libraries everyone has, because there is no concept of digital resale (even though we really should come up with something.)
There are many ways to look at things, and some are funny:
When I buy a game at 60$, and sell it at 40$. Theres not profit here. People doing thing is losing money. Bethesda should be pocketing the 20$ that the guy selling the game is losing. A alternative would be for Bethesda to pay 60$ when I return a game I paid 60$.
Also Bethesda run on Windows and Nvidia drivers. Microsoft and Nvidia should receive a cut for every game Bethesda sells. Bethesda profit on other people work, without paying for it.
Am I allowed to sell paid mods as “New” for their totally 100% original in-house Fallout and Doom franchises?