...Sales will migrate, the market gets proved, and all the old toads holding consumer nooses, will let them drop and follow the new model, or they will wither and die from lack of sales.
Sadly it doesn't happen like this. Germany based digital distributor gamesload.de offers a transferable license for years now (all games except EA) and nobody notices. Sure prices are not that low as with Steam, but the service is not getting more publicity nor increasing sales whatsorever. It's only one example but contrary to what you predict. Either people are too lazy or they put much less emphasis on the importance of used sales than you or me.
Btw. That also shows that used digital sales are possible and the world is not worse because of it.
I think you did not notice something in your own post. Whatever games load did is irrelevant as just like you said. Nobady notices. Their actions have no impact sans why the world is not worse off.
I am for whole account trades, game in your inv or simple key trade. Not games themselves which I played. How do you imagine gog system working, massive sales... If people can trade "used" games we won't see massive discounts nor any discounts for that matter.
If it happens I hope Germany will be isolated when company stop doing business with the country, otherwise everyone will suffer.
This might already be linked to in this thread: http://www.gog.com/forum/general/europe_it_is_now_allowed_to_sell_used_software_cd_and_digital/page1
Personally I don't see the difference between a license via a DD outlet or a license via a retail store.
In both cases I own the license, only on a different media. Which means in both cases I should be able to sell that license.
I also don't see a difference between games and (e-)books, music and videos when it comes to selling used items.
As reselling means you're not allowed to own a copy, the only way to enforce that is DRM.
As for companies leaving countries which allow/enforce reselling, that has to be seen. If they can still make a profit, they'll stay. Less profit is still profit.
I'm not sure if the combination of big sales and reselling will work. I expect less sales or less discount on sales.
There is no such thing as used digital goods. This is the difference between retail and digital.