Also sometimes you have to look harder than usual, because the presence of an RSS icon only loosely correlates with having actual feeds. Sometimes things like domain.com/feed, domain.com/rss, domain.com/atom yield success, I suspect provided by the website engine itself.
Not to take away from your argument
- sites without feed: These sites usually have a Facebook page so i added a feature to subscribe to a Facebook page. The page posts now appear in your RSS feeds as regular RSS items.
- noise: The content is automatically categorized, with names of people, places, etc... extracted so you can easily filter your feeds. Articles in your feeds are automatically grouped together if they're about the same story, that helps reduce the number of items and at the same time provide different angles on stories.
- truncated content: There's not much to be done for this one i guess, unless you go against the publisher's wishes
Another problem is truncated feeds, requiring users to click links and navigate to the original site to read each item. While some premium readers claim to offer complete news items, this is probably against the wishes of the site and may be circumvented similar to the add-blocker arms-race. In my opinion if a site model requires users to visit it, then they shouldn't offer feeds at all.
Lastly some feeds are behind logins (e.g. forums), not all readers support these feeds.