Ignorant!

It's significant, but hardly 'very' expensive. The costs of peer review are less than 30% of the total direct costs of publication and distribution of scholarly articles. And that doesn't include the indirect societal costs... See http://blog.openwetware.org/scienceintheopen/2009/03/03/what-is-the-cost-of-peer-review-can-we-afford-not-to-have-high-impact-journals/

Peer review could be done on a post-publication basis, as suggested by the article I cited.