If games are $70 at launch I could see a lot of people using the consoles for non-gaming purposes and buying fewer games or more downloadable games.
This is a unique challenge that no other generation has had to face. Now that these machines do so many other things and also have an online market place of cheap games there are many alternative ways to use the new consoles. In the past the only thing you could do other than play games was watch a movie on DVD.
Yes at 360 launch there was Geometry Wars and a few other games, but it wasn't much selection. The quality of downloadable games has increased drastically in the past 8 years and the available functionality of consoles is increasing exponentially.
Just raising game prices to $70 isn't going to do it and forced bundling may price these machines beyond demand, there's going to have to be some creative ways of minimizing losses, whether it be paywalling used games & legacy games, subscription services, season pass requirements, advertising; IDK. This is the problem with the hardcore game industry. Making games is getting more expensive and fewer people are going to be able/willing to afford these types of games. Demand is going to have to be super high for retail store bundling to work at $70/game.