Culture plays a huge part too. I was speaking to one of my Chinese friends the other day and was struck by something she said about the popular boys in her school. I asked what made the boys popular - she replied that, amongst other desirable traits, they got good grades. Needless to say this does not apply in any western society I've been a member of. Rather the opposite, in fact.
In a society edging towards post-scarcity, perhaps the desirability of conspicuous displays of wasted energy, like being "cool" or whatever, move to the fore. But in a society still climbing the developmental ladder, I just don't see it. Not to say that the theory lacks any merit at all - the conspicuous waste thing could well be a big factor, like how people buy ridiculously expensive watches just to show they can. But I don't see how it "evolved" when even the west has been like this for only half a century or so.
A more likely explanation for the sexual allure of popular musicians is their perceived wealth, exciting and interesting lives, boasting rights over ones' friends, and over society in general. The same thing can be seen, mapped into a different context, in the Chinese experience - good grades at school = good university = good job = all of the above benefits. I would posit this is a more likely explanation than the "evolved waste" theory.