Is the idea that “you can’t learn a language with a single app” legitimate?

Edit: I don’t really think an app like this should exist, this is purely a discussion post on if you think it *could* exist AND actually make you fluent. Every time I see someone talking about a language learning app they invariably say “you know, an app will never make you fluent in a language” I always have this nagging voice in the back of my head saying “Never? Really? Never ever??”

I want to discuss the idea that one app could never be a one stop solution, I see that statement thrown around a lot but realistically, why not? I think one totally could, like if you had an app that gave you reading, writing, speaking, and listening in one place, you could have a one stop shop.

And not like what Duolingo does where you randomly jump from one skill to another and practice each skill for 5 seconds while they hold your hand. I mean straight up combining full fledged tools dedicated to each skill while allowing you to completely focus in on that skill without distraction.

Like maybe LingQ for reading, Pingo/italki for speaking, something like Snapalabra or some other AI tool for writing, and Spotify/youtube videos for listening. Throw Anki on top of it for vocab. And then carry the user through a lesson plan specifically for grammar A1-C1 (I’ve seen a lot of apps specifically for grammar but most of them are language specific)

It would be one hell of a massive app, and take a lot of work ontop of it to not feel wildly disjointed, but would that not suffice the requirements of being a single app to learn a language? Sure nothing fully exists like that today, but I do believe it’s totally doable.