The question is really only: Will users actually want to continue to use these services once the novelty wears off? The assumption is that they are useful enough to become an integral part of our lives, but time will tell...
I don't see how suddenly hundreds of billions of additional ad revenue will appear.
I think some of AI companies truly wanted to make a fortune replacing all white collar workers through model exclusivity, but that open models (initially Llama and then a sequence of really good Chinese models) threw a wrench in the cogs. There is not as much you can make anymore if everyone can host their own 'workers' near cost price.
They might lose entirely (search, social media, etc.) if users are more likely to direct their eyeballs to "AI" services. And that isn't an impossible scenario. What do you need traditional web search, stupid internet comments, etc. for when an LLM will generate all that and more immediately at your behest? The newspaper companies lost when other forms of media came along. "AI" could easily push things the same way.
But the businesses are still trying to prove that. It is still early days. Only time will tell if they will actually get the aforementioned user base.
But LLMs do have some niche, stable applications already. For example, they replaced Stack Overflow to a large extent, because you can get the answer you need faster, and it's often better adapted to your situation. So you could argue the novelty of SO wore off a long time ago but people were still using it when LLMs appeared. ChatGPT is no more en vogue, people are ashamed to (and shamed for) using it, but it still has some uses, helping people in their jobs and lives in general.
I mean, should it all come crashing down and once the dust settles there is no doubt room for a niche service to rise from the ashes. Many have predicted exactly that AI will have its own "dark fibre" moment. But the current crop of providers seeking "world domination" won't survive if they can only carve out a SO-style niche.
