The next gen consoles not accepting used game's is irrelevant on the price of the current gen's used games. Your second question is a bit confusing, the prices on the current gen of game's are for the most part gonna become less valuable as more games come out.
People buy the games used because it's cheaper then new. I don't see any reason the current gen would increase in price just because the next gen doesn't accept used. They might have to lower the price on new games for the next gen because if there's no way to trade in or sell them, then less people will buy them at full price as they currently do. There will definitely be some implementation of used games on the next console. I mean otherwise rental companies would get killed, PLENTY of game stores would get killed.
Think about it, gamestop (While not the ONLY place to buy games) still sell's a MASSIVE amount of New Games/Consoles. so if the console were to not accept used games (which is downright ridiculous) than Gamestop probably would refuse to stock the console.
That is a MAJOR loss of sales from that standpoint. People seem to not think about that standpoint.
I'm going to guess there might be something along the lines of games forcing install's and then having the disc be able to authenticate and allow the game to play, at least for the X1. (Which makes the "Must connect to internet every 24 hours" make sense for the Xbox One) That way, you can't just duplicate a disc, or burn a copy, that disc is tied to your account, sorta like a cd key (That is the physical CD). But that disc is transferrable, as would the CD key, so when someone else has the disc, they can enter it, tie it to THEIR account instead, which would then cause the last person to lose THEIR access to the game.
It's probably gonna be more a DRM reason then anything else. It would pretty much stop pirating because the console would be able to check every 24 hours if the game being played was authentic or not. (Missing the unique on disc authentication) and if it was a pirated copy allow for action be taken. No longer can someone just play a burned game offline from a hard drive.
Other than that I don't see universal online passes happening, EA said they don't work, and I don't think Microsoft ITSELF would MANDATE them for every game.