>Reddit-like voting and commenting site for scientists would work just as well to vet papers

Probably not. There's a well-known essay that explains why karma/votes/likes work very well for easy tidbits like cat photos, gifs, and puns. (The stuff that takes less than 5 seconds to evaluate and requires near-zero effort to judge whether one "likes" it or not.) Unfortunately, I don't have a cite because I forgot who the author was.

Longer topics such as a 20000 word dense research paper with supporting data that requires at least 2 hours of study by a reader/reviewer doesn't work for a karma points system. The effort is too high to contribute
significant # of votes. It's the same difficulty for other long form content such as manuscripts for novels/books.

Instead of karma voting, these works require curation that passes the "signal of approval" from one person to the next. With book manuscripts, curation is first done by the literary agents and then the acquisition editors. With scholarly papers, it's a somewhat analogous process (committee 1st pass then forwards to the peer reviewers). Each "approver" has a reputation which signals to the next person that it's ok to invest the hours into studying the work. This social signaling mechanism is also similar for startup entrepreneurs' business plans and VCs. VCs would rather be exposed to your business idea from a referral rather than an unsolicited cold email. All 3 domain examples of book manuscripts, academic research, and business plans share the same theme: people have limited time to wade through a vast sea of poor quality content.

I think people can conclude that flipping through 100 cat photos is different than slogging through 100 dense papers. Another example of this dynamic is the Stackoverflow voting system. There have been several meta discussions lamenting the fact that the "easy" questions attracts a high volume of activity (answers + votes) but the "hard" questions languishes with little attention. That's because the easy questions are more analogous to the low-effort cat photos.

Another commenter in the thread mentioned that github solved workflow for programmers and the same could be done for peer reviewing academic papers. This is misunderstanding the underlying issue.

Evaluating dense papers is not an "information technology workflow problem" that's waiting for collaboration software to solve. The bottleneck is human effort to properly read papers to judge its correctness and significance. In 1687, a human would read Newton's Principia Mathematica at ~200 words-per-minute and after several hours, maybe he'd conclude that "yes, F=ma looks reasonable here". It's 300 years later and we're still the same slow humans reading papers at ~200 wpm. It's worse now because there's a larger glut of bad papers to wade through than before.

Peer review of novels, scientific papers, business plans, is not solvable by a Github/Sharepoint/DropBox. The bottleneck isn't the copying of pdf or LaTeX files from one person to the next. It's the hours of human effort to judge the papers and signal to the next person to also expend hours of human effort.

The issue about publishers isn't the filtering. The real issue is that they they charge too much money for filtering. The high profits is misleading some people to think it's an easy problem solved by github or a reddit-like voting system.