Those who have a lot of Steem Power vote for themselves or in a group amongst themselves, that's why a lot of junk gets high rewards.
The system concept is flawed. There are billions of people in the world, imagine having to follow a billion people that post 99.99% junk, there is just not enough time to do it.
That's why I say distribute rewards according to one' steem power, and if you want to reward a post you take it out of your own wallet.