There is a possibility that it might just be the games. If you've been playing a long time, it will be harder to present something to you that is actually new, interesting, and well done.
It's why, as much as I keep saying "I wish there were more games like such and such". In reality, trying to make more games like classics of old won't work. You say "I want more games like it" but you are really saying "I want games as good or better than this."
It might be shocking, but classics are classics for a reason. They aren't just going to be able to crank them out like it's nothing. And an indie studio is not very likely to do it on their smaller budgets.
It's like playing Super Metroid and then going "I really want more games like this!" but then being a little dissatisfied. You played the best one, it's only downhill after that.
I know the exact feeling you are talking about. It still happens occasionally. When something quite unique and well done comes out.
And I think there is also an issue of game developers not really sure what they are doing anymore. They aren't taking the big risk. They aren't pushing the envelope except remaking older games but with new technology.
Like look at this.
en.wikipedia.org/wiki/1998_in_video_gaming
That was a fuckin amazing year. But look at the year before or the year after. Same thing. Now fastfoward and pick a more recent year like 2008.
en.wikipedia.org/wiki/2008_in_video_gaming
There are some great games that came out that year, but it's a lot more underwhelming.
Basically, I think the two relevant variables: you and the industry, both have a sort of push-pull thing going. Where you have already played a lot of great games, and the industry has just stopped releasing them. So it feels like "Where is all my passion for gaming? Why is it gone?" Well assuming you just want to play good games, you don't really have a lot of options.
Oh also, side note, I think there is a friend aspect as well. A very fun part of playing games was playing next to, or with, a friend. And then talking to a bunch of people at school about it. It was a solo activity mechanically, but ultimately a social one as well. Most adults don't have that at all. You play it, that's it. You can go to Holla Forums to post about it, but most people will either say "shit game fuck you", have not played it, have played it and don't have anything to say other than "great game 10/10", or someone will start freaking out about dubs.
I wonder if anyones ever tried a book-club style gaming social. See how that works.