Bots should automatically stop accepting bids once ROI hits negative percentages obviously it's just costing everyone money.

They should do no such thing. You're missing the point of pay-for-vote. It should never have been about ROI on an individual post. People who are going for ROI are get getting what they deserve.

Expecting an ROI is insane and unsustainable. It would be death for the platform. It would be BitConnect.

The purpose of bid bots is to get exposure you wouldn't normally get. If you post something that nobody sees, you can pay for a vote. It's like paying for ads on Google Adsense. Can you imagine if people complained about not getting their money back from using Google Adsense?

If you don't make money from Google Adsense, you stop using it and find another strategy. But what you're suggesting is that if people can't make money from using Google Adsense, Google should stop selling them ads. That's idiotic.

Ad campaigns never look for ROI on individual ads. They use campaigns to build exposure over time. Once they reach a certain level of exposure, they end the campaign and see how they do without continuous ads. Sometimes they resume their ads or they change to a different strategy.

If you aren't getting more readers after paying for a bunch of upvotes, you should consider that you might have bad content.