Apple was nice enough to call me on the telephone to discuss my rejection. They wouldn't say why auto-renewable subscriptions can't be used by non-publishers.
My suspicion is that they want to prevent app authors from using a SaaS-like monthly billing model. Whether this is due to customer confusion or their own distaste for monthly billing I can't figure.
It seems that developers have to take the backseat unless they want to miss out on the ride.
A lot of Apple's thinking can be explained through the eyes of the user. As a user I'd hate for apps to continually bill me unless I expect it (which I would in case of a publication). As a Developer, I can see where SaaS billing would make sense and would like to have that option.
