Most of those websites have been complements for Google Search rather than standalone services whether they like it or not, and if chat bots replace Google Search, they'll replace the entire ecosystem.
Not that this matters, because Google search alone disproves the claim that people only use phones for videos and social media.
I do personally think that we'll see regular users interested in new, different workflows than the automation ones we associate with power users, and the image generation use case you mention is a good example. Chat-bots do seem to be owning those rather than entirely new apps.