If a worker can generate a large amount of income for their employer from their efforts, why shouldn't they receive a fair share of that? Is it greedy to want a fair share of what they create, rather than have others take it? This money doesn't come out of nowhere, it is there because millions of people are willing to pay money to be entertained or informed by them.

For example, if Adele can fill 90000 seats at Wembley stadium at up to £100 per ticket why shouldn't she receive a substantial chunk of that? Or should she accept MU rates and see the bulk of the money go to others?

For TV presenters it is a little more difficult to apportion value, but commercial operators will know the size of the audiences they attract and the value of advertising and subscription income that can be attributed to them. The operators are businesses and wouldn't pay these sums if they didn't think it was profitable for them to do so. The BBC isn't a business in the same sense but it has to compete for the same people.