Read this. http://rosbarber.com/authors-truth-money/
It’s by a British author but I supect things work the same way in the US. My own book has fifty 4 and 5 star reviews on Amazon uk and has been short and longlisted for two literary prizes. Amazon sells it for £8.99 a copy — of which I get around 20p. It will take me a very long time to make a living at that rate. Like most writers I know I have to teach. No one owes me a living if no one buys my book but when they do I think it would be just if my publisher and I got a fair cut of what my book is earning for the retailer. After all I did the lion’s share of the work.