The 3 posts could even be rotated in proportion to the value that was spent on post promotion, competitively encouraging people to spend more to gain visibility.

This is exactly what I was thinking.

SteemPeak used to do something like this

As far as I know ecency.com does something similar and since it's open source, we can even borrow almost ready-made code from there 😉. Although, I could be very wrong about this.

I'd say, "yes" and "yes".

Here, too, our views converge.

This part literally made me laugh out loud

Well, I like to add sarcasm and jokes to my posts, even if the post is supposed to be very serious. I can't do anything about myself 😄.