Well, I mean... would you mind people giving you bad ratings, if they had to pay you for the privilege of doing it? Authors could even determine their own price, right? Half a Bitcoin for a 1⭐  and you can put whatever crap in the comment and we're good. 😅  Two comments and I retire.

https://c.tenor.com/_rafdjAM5zIAAAAC/tenor.gif 

 That's, again, a lot deeper than I was thinking. 

But, that could also be a bad thing. I don't think that it should be possible to set a minimum price per star rating. It would be better to have one price to rate at any star. If that's the system to go with.