Nobody is doing well enough with AI revenue ATM (https://isaiprofitable.com/). At the moment it is probably more about market share of users, that is where the investment capital will need to be clawed back from when it starts to be called back (or replacement money will need to come from if the investment cycle simply stops giving generously).
[couldn't resist the snark, I don't exactly feel sorry for them here!]
They'll probably be less annoying than ads in Google Search results, because people ask LLMs more detailed, context-laden questions.
I expect aggregate ad revenue to climb, so this might sting less, but much of Google's stock price imputes their dominant market position (and implied moat). A large proportion of users don't first navigate to Google anymore. They ask ChatGPT. Commoditised LLMs (or worse, a dominant provider which isn't Google) is a very bad scenario for Google.
I think they're going to have to diversify. Cloud compute revenue keeps climbing. Their deal with Apple for "small" LLMs suggests they might have opportunities to specialise models for specific tasks. They still command a massive lead in things like Maps and Gmail, and they can lean on those.