Everyone would notice they're doing it. It would be really, really obvious if whales were colluding to abuse the system to extract rewards. People would not want to be a part of the site after seeing something like that. The site wouldn't last very long, and their Steem Power would be worthless...
The whales have a lot at stake and they want the platform to succeed. Being a whale means you have every incentive to prioritize the long term health of Steem over any short term gains you might receive trying to game the system.
youre saying theyre not doing it?... can you find me a whale post that didn't make 5K+ dollars?
Yeah theyre doing it, yeah everyone notices, yeah its driving people away.