The reason is that only 1% of users holds more than 91% steem power. The number of newcomers is increasing, all try to write posts, but the number of whales is the same as despite power down they still receive great reward as stake holders. As a result, whales can not upvote every good post and many people, despite great content, become unrewarded. That's why people prefer to vote for people who is with great probability will be upvoted by whales and dolphins. This is current situation.