I've always found the lack of a secondary market for digital goods interesting. If done wrong it would certainly screw the publishers, but a system like steam that already does have a market for their trading cards and some other in game purchases could implement a publisher tax. 25% of resale goes to the publisher or something of that ilk.

I am sure if I actually read the EULA it would state something about single party license that is not assignable.

But yeah, what if you let market forces control the price entirely? Launch day only release X copies and then Y copies every day after. Have a market bid system. Most games don't have long term value so prices would naturally decline over time. An interesting thought experiment.