You have a point, yet I cannot agree with you. The fact that people are willing to pay a determinate amount of money for a job does not mean that job is worth the money. If it were so, there would be almost no swindlers in this world. I can never think that what Paris Hilton does is worth more than, say, a doctor who saves lives. I even find it immoral. And what some talentless celebrities do can be, in my opinion, defined as a swindle towards common people. Do you think that if people were not o stupid to be interested in them, they would be making any money?
Again, a ridiculous argument. How do you define "worth?" The way you're defining it is "how much I value it." The only way to objectively define it is "how much, taking everyone into account, is it valued?" Your swindlers analogy is a really valid point and i'm impressed by your thinking. - swindlers lie about what they're selling.
<i>You</i> may not value what an actor or other celebrity does very much, but evidently a lot of other people do.

EDIT: Actually, it's not even a matter of values. In a celebrities case, it's more like an investment. A actor, in effect, gets paid by every single person in the world that goes to watch his movie, because he gets paid according to how much revenue he'd generate. A doctor, on the other hand, is only paid by the patients in his area. More people "make use" of an actor, because a movie generates more revenue than a single doctor. But again, why does it matter to you what someone else is making?