I'm not sure about OP's situation, but I know for me a lot of it has to do with lack of time. I loved gaming when I was a kid, and still do. But when I was a kid I had much more free time on my hands (although I definitely didn't realize it back then!) Now that I am an adult, I have much more responsibility than I had as a kid. I work around 50 hours a week, and usually by the time I get home I have just enough time to prepare and eat dinner, watch some tv, and go to bed. Any free time I have past that goes towards mowing the lawn, maintaining my house and car, and spending time with my wife and son.
Assuming you have good parents, life was probably handed to you on a silver platter as a kid. Sure, you had to go to school, and I remember some nights working past midnight on homework assignments, but aside from that you're pretty much free to do whatever you want. I chose to get a job when I was in Middle School, but that was my choice and it gave me some extra spending money. My parents paid the bills, I didn't have to pay for rent, electricity, water, etc. I didn't "value" my time as much as I do now, because I still had plenty of free time. (and of course if you tried to tell me back then that one day I wouldn't have so much free time, and that one day I would miss it, I probably would have said you were full of shit...)
As a kid, time spent playing games added VALUE to my life. I lived in the middle of nowhere, there was nothing fun for a kid to do. No movie theaters, bowling alleys, skate parks, and had to drive out of town if I wanted to buy something as simple as a pair of shoes (or a video game, for that matter.) Video games allowed me to go on fun adventures, and explore imaginary worlds. I could be a wizard and cast spells in an RPG, or be a commander of an army in an RTS game. First person shooters and fighting games were a great way to relieve stress. And I love playing Pokémon, and battling with friends.
Now, I have very little free time, and other responsibilities take priority. Video games cost lots of time and money, and while I do find value in games, I find more value in spending time with my wife and son. It's hard to justify spending money on games when I have bills to pay, and a house to take care of, and a car that needs new tires, or an oil change, or brake pads... My family needs food, clothes, school supplies, etc. Compared to these things, video games are on the bottom of the totem pole. That's not to say that I don't like them, I still have fun playing video games with my son, and I still enjoy getting a nostalgia high when I pull out my old Super Nintendo and blow the dust out of my Super Mario World cartridge. But priorities have changed, and it's understandable.
Life is too short to find yourself at 60+ years old, only to look back at your past and say "I've done nothing but play video games. What have I done with my life?"
