Just for a different perspective, my kids spent zero time in the clubs.
DS15 ad DD12 had no interest. We went and toured as a family on the first day. We met the counselors who were all very nice and seemed like cool people. My kids had great conversations with them and also with some other kids walking around. they even played foosball with another bro/sis pair we met in Vibe. The spaces, both Edge and Vibe were awesome.
We had all planned for them to go to their respective meet up in the clubs after dinner that first night. However, dinner was a little slow that night and we were having a really good time getting to know our fabulous serving team that it was kinda late when we were done. We were also exhausted and the kids asked if we could just go change into jammies and walk around the ship and do the Midship Detective Agency. We didn't even make it back out for that, an ended up lounging in the room and getting to sleep in anticipation of our Nassau excursion at 9am the next day.
Every night pretty much went the same way. Fun with each other and Mom during the day, awesome show and dinner with our fab serving team, ad more hanging out together and going to D Lounge for family karaoke, or a movie, or shopping, etc.
On the sea day I had them look at the Navigator to see if they wanted to join an activity in the clubs, and they wanted to do lots of things listed, but NONE of them were in the clubs. We did towel folding, Anyone Can Cook, etc but the club activities didn't sound interesting to them.
On several occasions we saw groups of kids milling around or playing in the elevator banks outside of Edge or Vibe on their way in or out. Often, the tween girls (in little bikinis) were giggling and talking about boys and chasing them or laughing while putting on glittery lipgloss or whatever while moving in packs around the ship. Similar to what you see at most malls on the weekends. On once such occasion my DD looked at me and said "I don't think the clubs are for me. I'm not into the whole giggle, make-up, chase boys around scene." Which is true. And I'm glad about it, too!
Just my experience with my kids, and since kids come in all personalities, maybe somebody out there also has kids who may simply enjoy being with Mom
P.S. Also wanted to add that my kids have lots of friends at church, in their homeschool group, and at the theater where they take acting, dance and music and perform in plays and musicals. My DD is in scouts and my DS is in the local HS Thespian Honor Society and participates in acting classes and plays there several times a week. All this to say that my kids are not anti-social, shy or not socialized. They were just interested in doing other things and being together as a family.