No chance for next gen. There are still a ton of people in the world with the money to buy games but without internet service that will allow for downloading of giant games in a reasonable amount of time.
Also, after the backlash MS got when they even dared to touch on the idea before release of XB1, I think we're still several years away from anybody having the balls to suggest this.
With that said, I could see a scenario mentioned above where some editions of consoles without a physical media drive are available.