You're talking about returns on SP through curation as if SP is an investment for those purposes, but you want to disregard actual ROI? If you can earn 25-30% annualized as a minnow and a whale is earning less than 10% annualized, how exactly do those returns favor the whale?
As an investor, you look at ROI. If you're not getting enough SP tokens because your SP is too low, there are ways to increase your investment in order to earn more rewards. That's how investment works. Nobody is stuck with only being able to increase SP through curating.
Your argument seems to be: If you make no investment into the platform, you don't get much ROI. Therefore, we need to make it possible to get larger returns without investing into the platform because having no investment is unfair.
It makes no sense.