She’s right: Her own image was more tomboyish than sexy.
It’s because they’re in a position to act out their fantasies — fantasies which are shared by lots of ordinary women.
Those singers and others (Janet Jackson come to mind) seem to go through a kind of later in life sexual awakening and break out of the good girl persona they started out with.
None of them are natural “10s” but suddenly they have the money (and the motive) to make themselves as “attractive” as possible, even this often translates into trashy.
They vaguely realize that they have a limited biological time frame in which to act and look this way so they try to squeeze in as much of it as possible.
Plus unlike ordinary women, they will be escorted everywhere, in limos, with bodyguards, so they can indulge their fantasies in safety.