This is a really weak comparison. Peer-reviews are used as a gating mechanism for papers unlike products on Amazon. Reviewers on Amazon don't have a say on what gets on the list and what gets off.

Additionally, published papers are often cited by other papers and peer-reviews are necessary to prevent a false premise from being propagated through citations unlike products on Amazon.

An Amazon review is not comparable to a review in a scientific journal. In a scientific journal a review is done by experts of the field and they invest a couple of hours / days. Scientists do this because it is part of their job. It is a contribution to the scientific community.

The academic reviews I write take me about one to three days of work. I have to work through a usually densely written paper, maybe read up on some background that I'm not entirely familiar with, develop a good understanding of the content, judge it, find places where the authors might try to hide some downsides of their work (it happens!) etc. Only then can I sit down and write an honest review.

This isn't the best comparison, since journals publish the reviewed articles, not the reviews themselves.

It's more like whether Amazon should pay the people who decide what should be in the Amazon Basics line, which I suspect they do.

Currency here isn't money though, but reputation (for the researcher and their institutions) and advance of science.

One can imagine a world where high-quality reviewing entities exist and attract top researchers without being profit-driven publishers.

I considered mentioning this, but the way it works is editors ask specific scientists to review articles for them (for free). The editor sends the article (the "product") for them to review, in advance of possible publication.

Sometimes people agree to review articles because they get to see research before everyone else.

Reviewing an amazon article costs 5 minutes. Reviewing a paper costs a day.

Journals extort hundreds of man hours per conference from reviewers. The largest cost of all, research and writing the paper, isn't reimbursed in the slightest and largely covered by tax payers, who then still won't be able to access the results because of paywalls.

The entire business plan of journals is to take research and peer review for free, and then sell it. Back when distribution was costly that may have made sense, but nowadays with the internet the cost of distribution is a fraction of what it used to be.

And anybody can make an amazon review. Very few people have the skills required to peer review a scientific paper.

You seem to repeatedly ignore people claiming that they are doing peer-reviews for free. I guess free facts are not qualified and useful facts ;)

The reviews are by and large free. I've known multiple phd candidates to be given papers by their advisor and they do the initial review for their advisor. Often these are additional reviews asked for by the advisor. That is to say, the advisor is usually not trying to avoid doing work, but they want their students to gain experience reviewing papers. Neither the advisor is paid for their individual reviews or supervised reviews, or is the student compensated in any way.

Amazon reviews are not remotely a good comparison. There is huge incentive in terms of experience gain, getting a bit of a sneak peek at research, and reputation gain(lets be real, its not that uncommon for people to be fairly confident they know who an anonymous reviewer etc is).

I'm not trying to make any point other than to add further disagreement to the idea that these reviews are not currently obtained essentially for free.

Attracting good reviews is the editor's job which is often unpaid too

do companies also give their products for free to amazon to sell?

Reviews are voluntary.

Peer review is not (if you want to keep your career, that is).