Or... if they hadn't tried to expand into "absolutely everything", you'd be buying from Walmart right now. Obviously you can second guess any single decision of theirs and try to spin that as "The Reason" Amazon is looking less dominant.

I'm saying that no, that's silly. They're less dominant because they're seeing significant competition, and the stuff you perceive as "worse" is the inevitable result of them having to squeeze on margins or expand into higher-hanging-fruit regions of the market.

And we're all richer for it. Don't buy from Amazon, that's fine. But don't expect to live in a world where you get someone else who can dominate a market like they did, either.