Oh you’ve never heard of Brad Pitman? You’re not familiar with his work? But you are familiar with Brad Pitt’s work, right? After all, he’s an experienced actor and producer with not one, but two, Academy Award nominations and a portfolio full of household names.
Bzzzt. Horrible analogy. Brad Pitt isn't worth what he's worth because of his portfolio full of household names. He commands his rates because he is a household name. People will go see movies just because he's in them. He's not getting paid for talent, experience, or attractiveness. He's getting paid for his personal brand. That brand all but guarantees that the filmmakers will earn a handsome return on their investment.
You, however, are an iPhone app developer. App purchasers have never heard of you. They will not turn out in droves to buy an app just because you worked on it.