To have ROI < 0 for all posts is not a bad idea at all.
This means people, only if they believe in the value of their posts will promote their posts.

For ROI>0 on value content, this would need someone to curate all the posts as value and non-value content.
Sometimes the border is very thin and bots,even humans can not do this.
The best is to comment it @themarkymark post. I am sure he will reply you back.

FD.