I think they do have one, it just doesn't look like a feed. It is "built in" across a number of apps on Apple devices like iMessage, Photo Streams, Memojis, Cal

I think they do have one, it just doesn't look like a feed. It is "built in" across a number of apps on Apple devices like iMessage, Photo Streams, Memojis, Calendar, and Facetime. They're even adding Status to iMessage in iOS15.