I can't say I know exactly how you feel here, but I have experienced something similar. For a few years now I've felt that need to game waning, to the point where I really try to discourage myself from buying a new game unless I really want it. Like so many others, the games will end up on my shelf played maybe once if at all. And even then, I can't be sure. I was really looking forward to Fallout 4, but I just could not get myself into it for the long haul.
Some of that is due to my loss of love for games rich with side content. I like the concept enough, but lately I crave a simpler, more focused game. Except for Skyrim - I'm still playing that for some reason. Yet, whether playing games or watching netflix, I lately get this strong notion that I could be doing something more useful with that time. Sure, games are fun, and I don't intend to give them up, but at the end of the day I haven't accomplished anything - I'm sitting where I was when I started. Most of the time I can ignore that feeling, but it keeps getting stronger.
Age could be a factor - I'm almost thirty four. But a lot of it likely stems from having an actual goal. There's always this thing I could be working on, and when I'm not, I feel like I'm wasting time. But I can't always work. I have to recharge those batteries, something books and games have always been great for.
In the end, I choose not to lament this feeling. I play games less, but I do other things more. I've even found that if I do multiple different things in a day instead of just binging on one activity, the day feels longer and more fulfilling. So I'll play games when I want to and I'll still love them, but when I want to do something else I'll put the games down and get to it.