I was dedicated to playing videogames more than I was to learning Japanese specifically.

Luckily doing pretty much anything in a foreign language will eventually feed back into your ability with that language, provided you make the effort to understand what you're reading / hearing. I think people assume that language learning has to mean lots of stuffy poring over textbooks. It really doesn't. That's part of it, but the majority of it is actually just doing things that you like in the language.
And I'm not particularly intelligent. Of course it's hard to give any objective measure of overall intelligence, but I don't think I grasp things any more quickly than most of my peers do, and I get pretty average grades in non-language classes. I'm usually at the top of my language classes, granted, but I think the reason I generally do better than others there is because they often make the mistake of assuming that classes are all one needs to become fluent in a foreign language, while I know from experience that classes only give you a very basic framework, and it's what you do outside of class that really counts.
In short, I think I probably have a better understanding of
how to learn languages than most of my peers do, but I think that's something born of experience rather than any innate talent. And if others spent as many hours using languages outside of class as I do and employed the same methods, I don't see any reason why they wouldn't have the same results. The problem is just that people aren't as obsessively geeky about languages as I am, and get fed up. :'D