When it comes to publication, economists set incredibly high standards. Compared to other fields, rejection rates are higher, editors and especially referees have a much higher impact, papers go through multiple revisions within the same submission (and may still be rejected), papers are expected to be self-contained pieces, and everything needs to be perfect, including grammar. All this leads to the well-lamented huge publication delays in Economics. Yet, publication in the top journals is still a requirement for tenure in any department that wishes to garner any respect, and it is just not possible for top journals to publish all the research fit for tenure.
Bruno Frey calls this the "Publication Impossibility Theorem System" (PITS): there just not enough slots in those journals, especially once one considers that 80% of the articles in the top five journals are written by faculty based in the US. Frey claims that this makes it impossible for non-Americans. Whether there is a US bias remains to be established, but even for Americans, the bottleneck is clearly present.
That said, this brings up more generally the question of publication expectations for tenure and promotion, and the journal culture in Economics. Over the last two decades, a large number of journals have been created, partly because commercial publishers saw opportunities, but mostly because the top, society driven journals failed to realize that the publishing needs of the profession have increased. It is only very recently that the American Economic association has realized that it missed the boat and created its four new American Economic Journals. The econometric Society as well announced the creation of two "field journals", Empirical Economics and the preexisting Theoretical Economics.
This should provide only little relief, as these add-on journals are unlikely to be considered top-journals. In fact they seem to turn into junk mail lying around everywhere in department mail rooms. What is really needed is to write shorter papers, straight to the point with less emphasis on the referees. More papers will then be published faster, and let citations then do the measurement of quality. The latter are a very imperfect measure nowadays, because the excessive lengths of papers allows to cite each and everyone. A shorter paper will have to be more selective and restrict itself on those that it really builds upon.