Think about it this way :
-> As of today, bid bots are generating direct income to bot users because there are not enough authors and steemit users.
-> Second step is when steemit will go mainstream. Bot will be used as they should be : an advertising service. You won't have an ROI from the bot but you will generate income from curators or from the product you are selling and which needs exposure.

Steemit bots are one year ahead of their time.