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.