> just now I searched for "phone charger" and the front page was mostly brands that exist solely on Amazon and some tiny Facebook page

This query betrays a certain level of naivety about the game theory of keyword-advertising.

Individuals who are shopping for a phone charger, don't tend to search for "phone charger." Instead, they look at the particular phone they already have, and decide they want a charger (or more likely, a second charger) that's compatible with it and guaranteed to make it charge as fast as it can. So they search e.g. "iphone charger" or "samsung galaxy charger."

We reductionist engineering-minded people might think "those are both just USB-A -socketed 5V1A DC switching-mode power supplies; and what do people call those? Phone chargers!" and so search "phone charger" — but that's a mistake.

The above individuals, because they're the majority, are what the brands are all competing over with their keyword-advertising spend. So when you search e.g. "iphone charger", Apple has paid to be there at the top; and the up-market third-party vendors like Anker who want to snatch your sale away from Apple have also paid to be there at the top.

But no individual is really just looking for an unqualified "phone charger", so when you search that, you get to see a page of stuff that nobody has paid Amazon for placement on; where instead, it's all ranked by how much scummy heuristic keyword SEO manipulation each listing can pull off.

(I say "individual", because there are institutional buyers who are really trying to buy unqualified "phone chargers", because they are buying them to install in e.g. hotel rooms, without any knowledge of what kind of phone a customer is going to have. So you might notice that there are some reputable brands in among these listings, but that the listings are for ugly unbranded flush-mount phone chargers, rather than consumer chargers. Commercial phone chargers, per se. Electronics that are components of a build, rather than standalone products.)

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As a tangent: the "happy path" for Amazon is actually all about browsing, not searching.

How do most people get to an Amazon listing? Not by typing words into Amazon's search box. For most shoppers, typing a keyword search into Amazon is done about as frequently as asking a clerk to help you find an item in a grocery store. And as with that flow, while it's certainly supported as a customer-service mechanism, it's never been intended as the primary item-discovery mechanism. Amazon isn't Google; they don't have a "so make a freeform text field for it, and let some ML find it in an index" view of the world.

Instead, people find things on Amazon mostly through these three paths:

• Searching a product category on Google, and then clicking through a paid keyword advertisement placed by one manufacturer that takes you to an individual Amazon listing for that manufacturer's product

• Clicking an Amazon affiliate link embedded in a review webpage/video, or as the target of an ad in Facebook/Instagram/etc.

• Clicking around on the Amazon website itself, starting on the home page; going into various "departments", looking through "Hot New Releases" and "Top Sellers", etc.

Approaching Amazon through any of these flows will land you on listings that somebody, at some point, paid to take you to. And that means that the category the listing sits upon is valuable, and is worthwhile to fight over. So in turn, all the "More items to explore" listings linked from that page will be that product's keyword-advertised rivals, trying to lure you away from the original listing.

The best way to shop for a humidifier on Amazon isn't to search Amazon for "humidifier." It's to search Google for "humidifier"; click through to a review site listing the best humidifiers (e.g. https://www.nytimes.com/wirecutter/reviews/the-best-humidifi... ); click through the first Amazon affiliate link you see on that page; and then look at all the humidifiers that are fighting over your known-high-value eyeballs on that listing page. Try it! I promise you it works. (The speedrun version of this process, if you already know a popular brand of humidifiers, is to just search "[popular brand] humidifier" on Amazon. All that brand's rivals will also be paying to show up there.)