I became a seller on Amazon two months ago, because I'm developing new (unique) products and I thought it would be simpler to have them distributed by Amazon.
But making said products is taking much longer than anticipated, so in the meantime, and as a learning process, I started selling one product in "private label" mode (ie, a product that I buy "as is" from a Chinese factory, with my brand printed on it). It's kind of selling, although the competition makes it hard/impossible to turn any profit (since all products are virtually identical, competition is on price and maybe listing quality/exhaustivity).
But what is amazing to me is that a service called "Amazon coach" regularly sends emails to encourage me to sell more PL products. Today, Amazon coach recommends selling a meat tenderizer on amazon.de: there are already over 350 different listings for meat tenderizers on amazon.de, how many more do they need???
Some time ago I used to regard the "ships from Amazon" or "Prime" logo as markers for quality, because I figured, somehow, that Amazon did some kind of vetting before accepting a product for shipping. That's completely wrong. The sign only means that the product is stored in their warehouse (and will therefore probably be delivered on time); but it has no meaning whatsoever regarding the quality of the product. There is zero curation.
Selling on Amazon is teaching me to trust Amazon less.
And of course, the ocean of similar products makes shopping much harder; meat tenderizers are not the worst case by far: if you're looking for a corkscrew in the Home & Kitchen category, you're looking at 2,500+ options on amazon.de alone... and 16,000+ on amazon.com!! Crazy.