You're not thinking creatively enough. One day, somebody's going to use the law and make the "sales" API-driven. This will then turn it into a rental service where you can "buy" a game for two hours for $37.50 and then "sell" the game back to the mother ship for $36.50 of credit. The mother ship being, of course, whatever VC firm puts millions into having the world's largest Steam account.
I don't have to like the current ecosystem of no-transfers and DRM, to acknowledge breaking all that down would have major economic consequences against studios. Right now is especially not the time to be asking for this, because the whole video game industry is in deep financial trouble at the moment.