WAV, I won't apologise for seeming idealistic :)! However, there is some pragmatism here as well; if you look at those performers who have sustained a career beyond the ephemeral world of the one or two hit wonder, there is generally a degree of real musical ability there, either in the performer themselves or in those who play/arrange/produce the music for them. I'm able to ignore (mostly) the taut tushed mimers, as you put it, and listen to what's actually going on in the music. A good example here is K T Tunstall, an English singer/songwriter. She could be viewed as a lightweight pop singer, but no; she is older than the norm, and has done the hard work of gigging with a band for some years before getting a break. 'Manufactured' boy/girl singing groups tend not to sustain, although they make a lot of money while they can. Those who do sustain tend to have talent; have you ever heard Westlife singing a capella with no amplification? I took my youngest daughter to see them some years ago. They stepped out from the mikes, and filled a large theatre with a really glorious sound.
There is a danger here though, and that's the pernicious practice of sampling the work of others and putting it out as your own; the recent offering from Kid Rock springs to mind, a blatant sample of Warren Zevon's Werewolves of London. Anyone with a mixer and a computer can do this now, thanks to digital technology, and it worries me that there is less incentive to develop original talent as a result.
Regarding the determinants; I forgot 'luck'!
Back to promoting your website I see. Sigh.
Tim