Richard Poynder has published "Has the Open Access Movement Delayed the Revolution?" in Open and Shut?.
Here's an excerpt:
As I said, publishers are also co-opting green OA. They are doing this by buying up repository platforms like SSRN and bepress, for instance, and by imposing lengthy embargoes before green OA papers can be made freely available. Again, the OA movement has assisted in this by, for instance, advocating for and supporting OA policies that accept publisher-imposed embargoes as a given, and by partnering with publishers in initiatives that turn repositories into little more than search interfaces. This has the effect of directing users away from repositories to legacy publishers’ sites (see here for instance, and here).