It's pretty typical behavior for today's teens with the amount of visual stimulation that most have been bombarded with throughout their lives. Add to that is at that age they are starting to have girlfriends/boyfriends and often have extracurricular activities or jobs that narrows down their availability to attend trips in the RV. I remember when I was at that age and my mom would always ask us to attend various functions with family and friends, there were so many that I missed due to a hectic schedule of playing sports at school and a part time job I had in order to have money for my car.
Our 4 kids (18-24 years old) on occasion will attend an RV outing, rarely all at once, if they can fit it into their busy schedules of work and school. If we are RVing within a couple of hours drive they may drive up for a night or two if time permits. DW and I thought that without the kids along it might lead to the end of our RVing days. Nothing can be further from the truth, we are now enjoying trips geared to more adult-oriented activities. In fact we are in the process of searching for our next rig and hope to find one that is better suited for couples and extended stays.