yes they created the iPad...and I paid for it! Why should I pay more after that? It's like Ford saying they want 30% of all cab income since they created the "Crown Victoria" taxi car....
(Is it just coincidence that every analogy in support of Apple forgets that second bit. Are the analogy writers unaware of that clause, or does it start to sound oppressive so they just leave it out?)
We can't view it completely from our developers perspective, because the average user just doesn't care.