I personally believe I'll never get out of anime. I love it too much, and I don't think it's something you can 'outgrow'.
First of all, most anime is based on more mature themes. Even shows that are targeted more toward younger audiences are still made in such a way that they can still be enjoyed by older audiences. Not always, but there's always exceptions.
Then you have genres such as seinen and josei that are specifically targeted toward older, more mature audiences. So, anime isn't like cartoons in the sense that they're designed for kids. There's something for everybody in anime. So that's why it surprises me a bit that anime isn't as popular as you think it would be.