There's an entire plotline in Startup where the main character is desperately trying to create an everything app after seeing someone in an Asian country with 1 app on their phone.

Spoiler alert - most of the development staff ends up quitting and it bombs on launch because nobody in the West is remotely interested in an "everything" app.

It exists. It's called android! Honestly though, that's why Google developed it. They wanted to maintain control and stay as the primary Internet portal for mobile users. Banking, messaging, gaming and productivity all passes through them.

We chat has similar in China but only because competitors were stifled. It won't work in the west as competition for any aspect will be better for some people and anticompetitive behavior will be clamped down on even if it started to work.