And if you make the apps composable then you get all the benefits of an everything app and still have the benefits of competition and specialization. Unfortunately even apps built on open protocols fall on the trap of trying to do everything on their own (look at how Mastodon implemented DMs in the worst possible way instead of delegating it to a chat app and how people keep requesting video hosting on Lemmy).

Was just about to comment the same thing. Unix philosophy should be taught in schools. Every high schooler that doesn't experience education-induced gag reflex when they see Windows is failed by the system.

I think the issue is that on mobile especially, switching contexts between apps is incredibly difficult compared to desktop and as such it's easier for one app maker to include everything so it can contest switch more easily. The "share" mechanisms on Android and iOS are great for the common use cases but harder for more nuanced things.

That and keeping you within their ecosystem drives engagement which increases profit.

Depends. Web browser? Absolutely not. Small directory listing utility (ls)? Of course.