Why do we still pay them so much?

Reading The Wealth of Nations, I came across this passage where Adam Smith attempts to explain the extraordinarily high wages of entertainers in his day in terms of compensation for public disgrace (Book I, X. Of Wages and Profit in the Different Employments of Labour and Stock):

There are some very agreeable and beautiful talents of which the possession commands a certain sort of admiration; but of which the exercise for the sake of gain is considered, whether from reason or prejudice, as a sort of prostitution. The pecuniary recompence, therefore, of those who exercise them in this manner, must be sufficient, not only to pay for the time, labour and expence of acquiring the talents, but for the discredit which attends the employment of them as a means of subsistence. The exorbitant rewards of players, opera-singers, opera-dancers, &c. are founded upon those two principles; the rarity and beauty of the talents, and the discredit of employing them in this manner.

I can see how this line of reasoning applied in the 18th century. But what would Adam Smith say of the equally (if not more) exorbitant riches we now shower upon Jennifer Lopez or Brad Pitt? They can hardly be said to be society's pariahs anymore. Yes, yes. I'm sure the paparazzi is rather tiresome. But don't try and tell me that the hardship thus endured is proportional to the compensation. And yes, both individuals are very easy on the eyes, but then again, there are thousands and thousands just like them waiting tables in L.A., willing to do what it is that they do for a fraction of the price. It's not like in athletics where the superstars have some real, measurable advantage, however slim, over the competition. Those who are hard-core free-market believers will no doubt say that since the market gave us the multimillion dollar movie stars, that must be, on some level what we collectively want. But why, dammit, why?