As far as I know Gmail, it lacks significant basic features of a good feed-reader. Like a button to mark all unread items as read, a function to automatically m

As far as I know Gmail, it lacks significant basic features of a good feed-reader. Like a button to mark all unread items as read, a function to automatically move to the next category/folder/filter with unread messages. Sure, I could do this manually, but that would be slower, more complicated and thus defeat the purpose of using a dedicated app for this job. And this leaves all the more advanced features, like sharing, different optimized views, all those little details which make a specialized app superior to a specialized app from another domain. Personally, I would love for Gmail (or some other mail-app) to be customizable enough to serve as a feed-reader AND mail-reader, and any other job we can fit into it. But somehow people are very focused on making apps only for single domains, and don't leak them to others.