Steemit is a platform that pays people to spam. This economic model is not sustainable in the long term.

Perhaps the creator reward inflation should be reduced towards 0, and the rewards themselves be paid from the ad revenue generated by the author's posts?

The assumption here is that the content creators incentives would now be on writing content that people want to see, as well as investing in the discoverability of the posts (sharing, backlinking, etc) - a big shift from current incentives of finding the most efficient way to siphon the reward pool.