SBL Papers on-line: why so few?

I commented earlier on the pre-SBL buzz and noted that there seemed to me to be fewer papers on-line than usual. A good proportion of those that are available are written by the bloggers, and Loren Rosson gathers a bunch of them together on The Busybody, with neat summaries. It is interesting but I suppose not surprising that bloggers are more inclined to put drafts of papers out there than are others since we are used to exposing ourselves (for want of a better term!) in public, so risk-taking, shamelessness or something has kicked in. But it does surprise me that more are not willing to make papers available in advance of the SBL. It certainly helps you to improve your paper -- you will get a good number of useful criticisms, suggestions, clarifications, extra bibliography and so on. And those like Loren who can't make it to the SBL this year get a taste of things. Others who will be at sessions get the chance to read a paper in advance of a presentation.