I've seen this cited so many times I had to dig into the root paper [1] The entirety is going to require some reading after work, is quite lengthy, but from a brief skimming I'm far from convinced that they're not inverting causation, and even if they aren't, they phrase their conclusion FAR more gently than TFA, leading to an interpretation that I find far more in congruence with reality: That there has been a confluence of games being better with real life propositions being worse for the demographic brackets in question. Even preparing for college and work 20~ years ago was an abysmal experience for me, and with the world as it is now, I don't know how I'd have found the motivation if I needed to do it again. And then you're posed with the alternative of a beautiful escapism, a world in which you have power, autonomy, a job you enjoy, and can work towards a better life? At the risk of waxing philosophical, if you want to make people play less video games, don't blame the video games; that's paramount to the mistakes we made back in prohibition. Focus on making the world for these people a better place so they don't need a respite from it.
A behavior will not typically be modified until the alternative is more appealing. It is not as simple to connect behavior to cause as this study implies without limiting outside factors.
[1] http://scholar.princeton.edu/sites/default/files/maguiar/fil...