2 or 3 console generations from now we could be looking at single-use discs. Or time-limited game discs. I mean if you're going to actively try and kill used sales, why not also kill repeat playthroughs with the same disc? Make people buy the game again if they want to play it again.
Considering that having enough content to want to keep playing it after the first 4-8 hours, or after you beat the game, is a major selling point, they'd have to be crazy to have single-use discs, time-limited game discs, or anything like that. Of course, if they did ban used games, that means people wouldn't be able to trade in their games which had a ridiculously short campaign immediately after finishing them the weekend after buying them, and would remove one of the reasons companies now make games with replay value, or longer campaigns, open world settings, excellent multiplayer, etc (Such as Borderlands 2).
But if anyone thinks that means they can just ban used games and then shove out only 6 hour long games like The Force Unleashed, and expect to get away with it, they're going to be disappointed when people just stop buying their games because they can't trade them back in, until the prices hit rock bottom from lack of sales (or don't and the companies go under). I already rarely buy anything on steam unless the price is $5 or below, or occasionally $10 or below. Once in a while I buy something higher-priced. I got Skyrim (probably should have waited), Portal 2 (That was a mistake), and Deus Ex: Human Revolution (This was an excellent game, and it wasn't chock full of bugs on release like Skyrim, either, and was worth $60) either via pre-order or (in the case of Portal 2) after release when the price dropped by $30 (Which was still a mistake. I wouldn't feel like I had wasted my money if I had only paid $5 for it; not because it was short - I enjoyed Portal but it wasn't why I bought the Orange Box - but because it was irritating and not fun at all).