The greatest value of journals isn't that three random people (give or take) have reviewed and suggested edits to the papers before publication.
The greatest value of journals is when hundreds or thousands (or, hell, dozens) of other people, well informed and competent in the subject matter, read the papers and consider how it meshes with their own experience and understanding and build upon it, writing letters to the journal pointing out problems and articles which follow up on the original work.
That is how an idea is validated. An article published in a journal that no one reads isn't much different than an unpublished article, and if work is spread, responded to, and built upon outside of journals, it isn't much different from a journal-published article.