My first WTF moment with Amazon was not long after they started offering free e-books, when I was browsing and decided on two. One was so old it was in the public domain, the other was new and independently published. The new book had no DRM or other nonsense, because the author had specifically forced it to be that way. The "public domain" one was so encumbered I gave up trying to Calibre it and spent the next hour blistering the air and offending God with my autistic diatribe. But Dad and I liked the free Prime shipping, so we kept gritting our teeth and sucking it up. Then one day Amazon demonetized one of my daily read websites for completely bullshit reasons - when the site challenged it, Amazon kept outright lying, shifting the goalposts and eventually just stopped responding. Dad and I politisperged and deleted our account, and since that day I haven't given those bastards a single penny.
If I were OP, even if I didn't cancel my account I would write a physical letter to Amazon sent by certified mail and CC 'd to the Better Business Bureau, the state's attorney and whoever else I could think of, calmly laying out all their sins, noting that this state of affairs is unacceptable, and demanding satisfaction for both my sake and that of the public interest. But I do recommend you bite the bullet and kick their ass to the curb, and convince all your neighbors and townspeople who aren't complete drooling sheep to do the same. It hasn't been hard for me to find alternate online sources for almost everything, apart from one regular use item where the seller told me they only sold through Amazon - I shrugged and settled for a slightly lower quality alternative that still does everything I need it to. Newegg has plenty of their own chinesium crapping up search results but is still usually my first stop for most PC stuff. For books, I recently found
https://www.thriftbooks.com/ which looks quite good.
My local brick and mortar selection isn't as limited as OP's, but maybe this is an opportunity someone should take advantage of. Yeah, I know - "just open your own store!" - but it's not impossible, if enough people get sick and tired of settling for not even good enough.
@Xarpho's Return: I had the same Costco issue of too much food for a single person, so I just split my food purchases with friends. Everyone wins and we only need one membership.