That's just weird, Clash gigs weren't full of teens. I saw them a couple of dozen times between 1978 and 1985. They had a pretty broad appeal (my uncle came to one gig and he'd have been in his 30s then). There were loads of teen bands about at the time, all the Two Tone stuff, Wham, Human League and the rest. I saw a lot of great bands in that era, Ramones, Stooges, Buzzcocks etc and some pretty dire ones too (The Exploited and Anti-Nowhere League) the audience demographics were pretty similar. So, unless you're saying Iggy Pop was a teenybob sensation, I must disagree with your assessment.