That's the thing. These different people don't bring similar value. When you work as a tv show star the value of your work isn't what you do but how many people will listen to you. You're not paid based on your "Senior TV Show Performer" role (or whatever title is being used in this industry) but based on your personality, your past and current successes, your potential awards, your negotiations skills, etc. If you can make the company feels that you will reach a large audience and that they will get a good return on investment, your market value will go higher.