There's a difference between used physical sales and used digital sales. Physical sales have the restriction that they might be damaged (Though they often aren't, they still have this perception with a lot of people), whereas digital copies are always in perfect state. Then there's also the fact that physical resale is harder to do than digital. (Depending on how excrutiatingly complex they make it, anyway). It is after all, near impossible for me to sell one of my games to another bay12'er living on the other side of the world, for example. This will mostly collide with the different pricings in different countries. One might buy were it is cheap and then sell it. Third there's the fact were it might negatively impact the sales.
Given these problems, we can devise a number of solutions
A) Evade the ruling, somehow
B) Divide steam on a per pricing group basing, each with it's own shop and such
C) Automated checking to see if no'one abuses the system for profit. This happens with the gifts system already
D) Pass a rule that you can only sell a game for the price you bought it or lower. This will prevent mass exploits to make money of the system, and possibly discourage lending games to friends for no money, as they would be worthless afterwards.
E) Take a share of the resale price
F) Go for Singleplayer +/ multiplayer only in game. You can pass a singleplayer game between friends and all get the same experience, but the same doesn't count for a multiplayer game.
Also, it might cause steam to go for an Always online DRM. After all, otherwise you could buy games on one computer(A), install them on another(B), and sell them on computer A. Meanwhile, as long as you don't let steam connect to the internet on computer B, you can play your games indefinitely.
G) Allow people to sell or trade their used games as they see fit (this is the correct choice)
I think at this point i should preface all of this with the fact that I'm not sure what's going on with this ruling. Most of the stuff early in the thread was conjecture based on everyones (probobly flawed) perceptions of what it meant. Steam certainly hasn't done anything about it so far, and I think I read a statement somewhere from them saying they weren't going to change their buisness practices at all. Though that may be why they slipped that class action suit in there (we're gonna ignore your rights because they're inconvenient, but you totally cant all gang up on us with a lawsuit!) Though that's probobly tin-foil hat territory. This is basically just a thought excercise at this point, but it's worth doing because I think people are far, far too willing to side with wealthy buisnessmen against their own interests for no reason other than "video games."
A, D, E, and kinda F would all be illegal under this law. F would be kind of illegal only because if you made multiplayer games some sort of subscription based service it would circumvent the ruling I think? But if it's a multiplayer game like say COD, or TF2 then you'd be well within your rights to sell them on or trade them.
B) I don't really understand. Do you mean like region pricing divisions? If so that'd be against the ruling aswell, and as such a violation of consumer rights.
C) Again, this is completely a violation of the rights as I understand the ruling defines them. I only singled it out because the entire basis of a capitalist economy is that you can buy low and sell high. The idea that you are somehow doign something wrong by selling a game you own at a profit over the original price you paid for it is insane. If you translated this idea into literally any other area of commerce you'd have entire industries failing overnight. Every single retail shop/store/outlet/whatever would have to close up. You'd have to buy everything straight from the manufacturer. Hope you live near a farm, or no eggs for you!
I'll say it again, because I'm worried every few posts are going to be someone new exclaiming "Yeah but physical copies degrade and the poor poor video game publishers need mo' money!"
Video game publishers do not need special protection from consumer rights laws. The idea that they do is thinly-veiled propoganda designed to make you feel sorry for the really cool dudes who bought the company that makes the games you like. Stop pretending that the multi-billion dollar international entertainment industry-running buisnessmen are delicate flowers that can't make money unless they get special exemptions from laws and rules that have existed since the founding of our civilisation.
Unless you can provide some sort of evidence that game publishers are running on like the thinnest of razor thin profit margins (you wont find any proof of this. Don't waste your time trying. They make a lot of money. Like A LOT of money) then don't try to excuse their horribly predatory buisness practices and steadily waged war on their own customers freedoms.
Don't be ok with trading away your own bloody rights for an entertainment product. Thing's like this are a lot harder to get back once you've lost them.