Clearly a lot of you are very young.....I'm a DJ and you'd be surprised how many people 30 and up frequent clubs. I didn't realize it until I graduated college a fear years back and so many girls I would talk to were in their late 20s to mid 30s, some had kids. You don't stop wanting to go out and enjoy life because you reach a certain age. Now yeah, you might not go out and club on weekdays like you do in your 20s but people def still go out and club occasionally. A lot of it is dependent on relationship status, kids, and just your personality. Most people don't club more because they're busy with work and when they get off just want to chill in the house.
but yeah if I wasn't into music I'd probably almost never hit the club.