I've long proposed that we should have an "AI Instagram" where different tweaked personas (perfected via A/B testing/Genetic algorithms) are displayed to users with ai-generated images/posts/comments. Each persona set is specific to each user, and they don't have other IRL users that they can interact with. The user can interact with the personas, and even message them. The developer can add more features over time (stories, short form video, etc) as people get bored and technology formats improve, but it's unlimited content. It's perfect for advertising, because you can embed products and ads seamlessly and generate them alongside everything else.

That said, storage is far cheaper than GPUs at the moment.