This is marginal value, the stuff that someone would give up in order to have one more of a thing.
A celebrity often makes money because, for whatever reason, nobody can easily and reliably produce an equivalent one on demand.
Folks working for wages in less-glamorous positions are doing valuable things for society, but fundamentally their pay is based on how easily society could replace them.
And you are guessing wrong. From what I've read she is probably one of the better people I would like to see in the role if "Billionaire"
I live in the middle of nowhere, don't have trash service, so I used to take it to the dump myself. Then my dad retired, and now I pay him a few bucks a month to take mine when he takes his. If this wasn't an option, I'd go back to doing it myself. This is why your local garbage man doesn't make as much money as Oprah. It's simple math and econ 101 supply and demand.
If your garbage man cost the community $80k per year, there would probably be 100 other dudes, all just as good at collecting refuse, offering to take his job and only charge $50k. That doesn't mean the disposal of all that waste disposal is not worth $80k (or $250k) to the community, but competition allows the community to pay less than the value it places on the service.
I bet there are also 1000 people lining up to underbid Oprah on whatever deals it is she is making with her partners(broadcast networks? advertisers?). But none of those people will attract nearly as many eyeballs. From the partner's perspective, it's simply a matter of choosing which TV personality will bring the most revenue (over and above their fee), and that's Oprah.
Also your above comment even says that "to the person paying them."
I pay Oprah and the garbage man, respectively, what they're worth to me.
I guess it hurts your feelings that Oprah has more value than your local garbage man, but it's just a fact.
You can probably come up with the reasons yourself: personality, name recognition, how easily replaced, etc.