Also makes me wonder -- where's the line? Is it reasonable to have "layperson" reviewers? Is it reasonable to think that regular citizens could review such content?
I think you will find that for the vast, vast majority of scientific papers there is significant negative expected value to even attempting to have layperson reviewers. Bear in mind that we're talking about papers written by experts in a specific field aimed at highly technical communication with other people who are experts in the same field. As a result, the only people who can usefully review the materials are drawn from those who are also experts in the same field.
For an instructive example, look up the seminal paper on the structure of DNA: https://www.mskcc.org/teaser/1953-nature-papers-watson-crick... Ask yourself how useful comments from someone who did not know what an X-ray is, never mind anything about organic chemistry, would be in improving the quality of research or quality of communication between experts in both fields.
That's pre-publication review, not scientific peer review. Special interests try to conflate the two, to bypass peer review and transform science into a religion.
Peer review properly refers to the general process of science advancing by scientists reviewing each other's published work.
Publishing a work is the middle, not the end of the research.
Also makes me wonder -- where's the line? Is it reasonable to have "layperson" reviewers? Is it reasonable to think that regular citizens could review such content?