Static rss file feeds?

I have to ask, is it really necessary to have an auto-generated for all the feeds? I maybe be able to see having one for +comments, but just posts? That’s a bit much. Why don’t WP just create/update a static RSS/Atom files when ever a post is added, edited or deleted? That would take a big load off the servers for any site that has popular feeds. And speed up feeds for slower trafficked sites.

Reason I ask this is because a feed does not ever need to be updated until a change is made to a post. The only exception I see to this would be +comment feeds, which can remain dynamic.