Not to mention that everyone from Walmart to what's left of Sears has online marketplaces to directly compete with Amazon's. Also, eBay never went away, with more than 85% of their sales being through fixed-price listings, like on Amazon's marketplace.

I know multiple people who don't buy from Amazon because they think Amazon is undercutting the competition. I don't buy from Amazon, because other markets are more competitive and have lower prices. The chance of Amazon having a lower price than eBay or Aliexpress are so low that it's not worth my time to look.

I find that Amazon is still the best for new, niche items like stationery. Maybe I need a Bayesian update