This is an excellent point. It makes one wonder why academic journal publishers even need to exist anymore. The peer reviewers (who don't get paid anyway) could just as easily do the same job and issue a "stamp of approval".
http://quantum-journal.org/announcing-quantum/ http://www.nature.com/news/open-journals-that-piggyback-on-a... https://www.aps.org/publications/apsnews/201602/arxiv.cfm
If one were to build a system along that line, meant to replace prestigious academic journals of today, of course it would be gamed. But isn't the general consensus that the current system already is being gamed and usually at expense of the researchers doing valuable research and the public at large?
(and in anycase, most subfields just have a couple thousand individuals involved at the PI level, who frequently interact at conferences, went to the same schools, shared an advisor, etc. So there doesn't really need to be an elaborate scheme to verify someones credentials. Chances are two individuals are already aware of eachothers reputations, or at least know some third party who is).