My one of my ex-girlfriends dad is in his forties and he's a pretty hardcore gamer. There's no age requirement to be a gamer.
Why can't you see anyone being in their forties or fifties and still be into gaming? Sure most of them right now aren't but that's only because most of them have played maybe 1 or 2 games in their entire life. Gaming is not of their generation. While our main form of entertainment is gaming, theirs is watching TV. Our parents keep telling us to grow up and stop playing video games, theirs told them to grow up and stop watching TV, before TV it was the radio and before that it was books. Also lets be fair, our parents love gaming too. While it might not be video games, they still enjoy board games and card games. In the end it's just the format that has changed but it's all about having fun.
Now will I continue gaming until the day I die? Well considering that I work in the gaming industry and assuming that I stay in the industry then yes I'll have to play them until I retire. As for enjoying them in my personal life then that will depend on how gaming will evolve in the years to come. Personally, I have a hard time enjoying it nowadays because I hate the majority of AAA games people praise so much and yes that includes The Last of Us. I hate how the majority of these games put so much focus on story that the gameplay just feels like boring filler in between cutscenes. If you don't know what I mean then try playing The Last of Us and skip all of the cutscenes. In the end it just feels like I'm watching a $60 movie.
Not only that but games these days are horribly designed. By that I mean that a game should teach you how to play it through level design and not through hand holding tutorials. If your game still has to show me tutorials half way through the game, then that game designer did a horrible job. Which is why I think Dark Souls is the best designed game in the last 10 years. Its first stage teaches you everything you need to know about the game as long as you think about it for a minute and question your own mistakes. The game also managed to create an incredibly dense lore and story simply by integrating it into optional NPC dialogs, item descriptions and world design. So if you don't care about story you can still go through it without reading a single thing, which gives a Metroid feeling to it, but everything is still there for you to understand the world you're in if you look for it.
I firmly believe that everyone should watch this video if they're seriously interested in getting into game design.
Anyway I kind of went a bit off topic there but it still explains why I may or may not continue gaming in the future.