I'm going to miss the Justice Society, but it seems that their whole existence is being written out in favor of making Superman the 1st superhero, and the Justice League the first superhero team.
I think there is a way to make it work, though: make it kind of like an superhero espionage group, in which a Justice Society with downplayed "superhero" elements was a secret government-sanctioned group of super-powered individuals who aided the Allies during WWII. When superheroes come out into the limelight thanks to Superman and all the new, modern heroes rising up on the scene, the Justice Society either comes out of retirement, or their descendants take up the slack.
I mean, it's not necessarily a perfect idea, and it'd probably upset a lot of purists, but something would be better than nothing, and that's all we're getting now.
And I'm honestly really surprised that for all this talk of attracting new readers and, of course, younger readers, DC still has yet to capitalize on the ultimate youthful wish-fulfillment superhero: Captain Marvel.