Take my father-in-law. He has zero interest in video games, comics, or cartoons. Yet, he loves going to Nipponbashi to check out speakers, amps, and old vinyl LPs. He's a huge audiophile, subscribes to multiple high-fidelity mags, and regularly goes to audiophile-type meet-ups. His set-up is quite impressive—nothing crazy expensive and much of it is decades old, but still wonderful sounding.
I was never really interested in audio equipment. I've always loved music, but I've never been picky about how I hear said music. My father-in-law has always been quick to loan amps and speakers under the pretext that he doesn't want his grandchildren growing up, listening to music from crummy audio equipment.
Sometimes I go with him to Nipponbashi—which is always interesting, because, as I previously stated, he's totally not interested in games and whatnot. Yet, he has a great time there looking at stereo equipment. It's a bit like when my brother-in-law goes there; all he ends up buying are model cars. That's one of the great things about these two districts in particular. They cater to a wide range of folks, not just the stereotypical "otaku".