There are a few presumptions you are making.

The first is that people use bidbots for the direct return i.e. X% on X STEEM. While this is often a reason, many use it for increased exposure. This helps them to get more followers which helps to increase their future returns.

The second is that presumption that bit bot owners are going to keep things as they are. I feel they will adjust their algorithms and added other layers that will keep then process enticing. With the increase in curation rewards, they simply could give part of that back to the users.

So if the goal is to make the use of them less attractive, I have a feeling that will not occur. They will adjust their business model to remain relevant.