Don't get me wrong. Stories is a very successful invention. It solves several important problems for the general public by placing an emphasis on rawness and ephemerality.
The fact that stories disappear after a while radically decreases the number of things to be consumed and creates a feeling of finiteness which is further reinforced by the compactification I mentioned above.
Feeds, on the other hand, often overwhelm people with their never-ending scrolling. Algorithmic filtering partially mitigates this problem by destroying the chronological flow and emphasizing the highly engaging posts, but it creates new supply-side problems and does not decrease the absolute number of outstanding posts waiting to be consumed. The already stressful process of content creation becomes even more stressful due to the added worry about receiving a high algorithmic score. People become more conservative and start emulating others who are already successful at "gaming" the system. Moreover, if they feel that they are getting filtered out, then they will simply stop publishing.
Of course, if the average person had followed a manageable number of accounts and created a reasonable number of posts per day, then there would have been no problems in the first place.
The reason why the feed structure is failing for the general public today is because it was born directly out of an analogy with the traditional publishing world, the world of celebrities.
Social media was an enormous success because it democratised fame, just like capitalism democratised money and democracy democratised power.* But it still needs some time to settle on the correct form. In particular, the structures people need to rise to fame may not overlap exactly with what they need to enjoy their fame.
Stories is a good format for the general public (i.e. amateur broadcasters starting off with no audience) because it takes into consideration our tendency to overwhelm ourselves and each other in costless, restriction-free** environments. Feeds on the other hand is a perfect format for celebrities (i.e. professional broadcasters with already existing large audiences) since it was born directly out of their own world anyway.