The #1 and #2 apps are non-coding, pure consumer AI applications (Meta Muse and Momo).
How do you add them? Inside the model has tons of problems. From user context makes a bit more sense, but how do you decide and how do you ensure the context is actually beneficial for the company paying for the ads (advertisers are very sensitive about what content gets subconsciously associated with their brand).
How do you make sure a human sees them? This is a very hard problem even in normal ads and seems even more problematic with chatbots.
How do you attract advertiser dollars? Ad spending is zero-sum. You must somehow convince advertisers that your chatbot is a better ad platform than Youtube, Facebook, etc.
The only AI solution that seems reasonable is something like Google's AI search because the RAG backend ensures Google can control where ads show effectively through deterministic means (based on the websites it pulls). Google also has the ad network, consumer base, and provable humans to drive up ad value (this is without mentioning that Gemini falls behind on coding/math benchmarks, but seems to be better at "normie" interactions).
None of this helps any of the AI startups and running all this extra stuff for the same ad revenue cuts Google's profit margins too.