I'm not sure, it was just never a question to me. When I was little I watched the Pokemon anime, and then I wanted Pikachu merchandise. And so, when I heard there was a videogame, I wanted that too. I played my friends' games, and then got my own and played those. It was just a thing I kept doing..
When my friends stopped playing, around the Diamond and Pearl era, I guess I just didn't even think about stopping. I was like, yeah, okay, you guys can go ahead and stop, but I won't. The difference is none of us watch the anime, because we feel the quality has gone down, but with the games the quality is going up. Sure, it was a pain to buy the new system, but... It's something I grew up with, so even if it's "childish", it's still something I love to do.