I don't think LLMs will be replacing Spotify, Facebook, Insta, or Youtube for my parents.

That's already happened. The curated feed you see is a machine-learning driven output of an AI model that Spotify calls a "Large Taste Model", supplimented by a host of models trained using Spotify's NEO framework. It might look pretty but it absolutely is the output of AI. I'd bet a fair sum that FB, Insta, and YouTube are also showing you the output of a model now rather than a traditional application.