Dig this argument for why inequality would get better on Bitcoin:

Bitcoin balances the economic rewards that go to investment vs. the reward for work by enforcing its supply cap and thereby rendering it impossible for invested money to "grow" consistently over time.  

On Bitcoin, the average return on investments has to be 0 because if it were consistently positive, there would have to be extra bitcoins coming from somewhere, beyond 21 million.

What are the flaws?  How can it be punched up?  How can it be conveyed in images?