I very often am in a situation where I want a "feature" (for lack of a better word that'd apply to any artifact of design) that's not there, and am left to infer why it's not. It could be because of many things:
In situations like these, it helps to ask around, if possible.
This weekend, however, I was wondering for the Nth time why there's XML files of all Mozilla/Firefox themes and extensions, but no RSSs of the new items in those files. I thought it was just that I couldn't find the RSSs. It turns out that it was because implementation was really hard. Most RSS feed generators take me only a minute or two to write, but this Mozilla stuff took me hours. It started out looking simple, but it was one complication after another.
Therefore in conclusion, delenda est Carthago.