What wasn't mentioned, but ties in with all the reasons given, is the link to the continuously dropping average level of intelligence (
VDARE.com: 12/17/06 - Is America headed for Idiocracy?).
It only takes a moderate level of intelligence to comprehend that not everything you are told is true (there are exceptions to this, but as a generalisation it holds true). If a person is able to do this, then the effect of mass media (the major player in this game) is considerably lessened. It's not entirely canceled out because the media preys on the public's weaknesses and everyone is vulnerable, some, just a lot more than others.
Therefore, lower average level of intelligence -> more people with greater susceptibility to the beauty promoting effects of the mass media -> overall increase in general opinion towards beauty having more worth than talent.
There is also a widespread belief in people of lower socio-economic status that beauty is the only (or certainly the quickest) way to become successful/get what you want. Probably because everyone can experience being beautiful (in some way or another, e.g. the high proportion of nail salons in Browns Plains, one of the highest crime-rate suburbs of Brisbane Australia), you cannot however, experience having talent if you do not possess it to begin with.