> I like the fact that the paper books themselves are copyrighted and no one can print them extremely cheaply and flood the market with them at my expense.
Having something that is paper doesn't mean that no one else can print them cheaply and flood the market. While it might not be at your expense - it certainly isn't something that is making you any money.
I don't self-publish on Amazon, though. I print my books in a local printing shop and sell them using my e-shop (Wordpress for blog, Woocommerce for e-shop).