This is all based on what I know from working for GameStop for 2 years. If the industry developers are stupid enough to ignore these things (hint: they are not.) then they are just going to fail miserably.
-Used games do not significantly eat into New game profits -from a Dev point of view! Retailers buy “units” from developers. Then mark those games up by 5-10% typically (profit margin at GameStop on a new game sale was like… 3% I think when I left.) So. That means developers GET THEIR MONEY BEFORE YOU - THE CONSUMER BUYS THEIR GAME. That is why retailers push pre-ordering so hard. They don’t want to buy more units than neccesary.
-Used games save developers from having to continue manufacturing old games. Which means, Call of Duty 900, Halo 1500 and Mortal Kombat Infinite can be their main focus. It allows new gamers access to older titles in their franchise, which creates demand for new titles to be made! It’s a self perpetuating marketing! Wahoo!
-The developer / retailer relationship is super super super strong. GameStop depends on their Buy-Sell-Trade model to keep their doors open, and developers depend on GameStop or other retailers to sell their product. Some titles sell themselves, usually franchise games, but others… Not so much. For developers to remove support for used games, they are pulling the plug on GameStop. Considering the amount of ass kissing that goes on (Free swag for employees. Including even giving away cash prizes or physical games for reaching sales goals.) towards GameStop as a company, I doubt the devs are going to do that… Any time soon.
-The consumer is not ready to move away from physical copies of games. So digital downloads are becoming more prominent, but not the main way of doing things. You can thank parents, and people who want to be able to sell / trade a game after they finish it for that.
I am not an expert or anything.. This is just some common sense conclusions I’m making from what I know about the gaming industry. Now, I wouldn’t be surprised if I saw Sony charge for all online accounts like Microsoft does. I expect Online Passes (ala EA Sports) to become standard (if you buy a used game you must pay $10 for a code to play online.) for most games. But I honestly do not see used games going away. Certainly not with this upcoming console cycle.