>One of the reasons Steem features posts with higher rewards in terms of visiblity is so people have the opportunity to scrutinize the post and rewards before payout, possibly downvoting if the reward is undeserved or outright abuse

I think the scrutiny of high-value posts to identify subjectively undeserved rewards is an important part of curation that is very hard to get right and people fortunately/unfortunately have been erring on the side of caution.