I've used the example of investors in a broom factory who are lured into investing with the promise they can take brooms from the production as a form of dividend.
Rewards for content creation are the product of Steemit, the mechanism that causes it to grow. Just as a company that has no brooms to sell will prove a bad investment, so will Steemit if rewards are similarly unavailable to deliver to content creators.
We see that Steemit loses ~90% of users YOY.
This is why.