https://pacheco-torgal.blogspot.com/2021/02/peer-review-may-2020-to-february-2021_28.html
Still following the post in the link above check the provocative article just published on Science in the link below. Yes, $450 may seem a lot for a single review but what if no money changes hands, what if the reviewers are just accumulating virtual money that can only be used to pay for open access articles or to purchase books or services like high-quality translations (or others) provided by the publishers? https://www.sciencemag.org/news/2021/03/450-question-should-journals-pay-peer-reviewers
In fact that already happens in MDPI journals that give reviewers 100 CHF (90 euro) vouchers but only for fast reviews. So a $450 voucher would mean that MDPI needs to increase its vouchers by 400% ! Surely journals would not go bankrupt if they start giving $450 vouchers to reviewers.
