> single purpose apps that work better than monolithic apps that do multiple functions

I would argue that iphone apps are monolithic and do multiple functions. For example Booking, Airbnb and Uber all have messenger, mapping, reservation system, calendar and scheduling function...

Why I have to use dozen different messaging system? Or several maps, each with different search and overlays. I want single experience, consistent across all apps. It should respect my usability settings, theme and other tweaks.