My understanding of Splintertalk curation rewards:
Most the larger SPT holders delegated SPT to Monster-Curator early on. Those of us who are late to the delegation party get less curation rewards due to how curation is set up on Splintertalk. Early voters on Splintertalk posts get more curation rewards (SPT Power is also a factor) then votes that come after. I believe some SPT whales are trying to change that but with no success thus far.