Yeah Youtube has no real competitor and AI shouldn't disrupt it that much, aside from the inflow of AI generated content which might be a problem on the storage cost side.
But most of Google's income is from search and AI/LLMs are killing it off pretty fast. Maybe they'll try to more forcibly inject ads into the summary output.
Anthropic, OAI, Meta, xXSpaceXAIXx all will need to put ads in their free models at some point. Google of course will too.
There is no future timeline where people are giving away compute for free. Right now we are still in the "Get them hooked" phase.