Google can grow their "search business" revenue without having to steam-shoveling resources into an AI furnace at an exponential rate.
No, they can't. They're already seeing searches decline as people move to asking LLMs instead. The LLMs actually end up using Google, but that doesn't generate any ad revenue for Google (that's something Google may have to figure out how to put a stop to). The solution so far is the addition of "AI results" to search output... but those AI results are produced by a far inferior model because Google search gets hundreds of thousands of queries per second, and it's currently infeasible to service those queries with a full-powered model. But the output of the inferior model doesn't satisfy users, so many of them are shifting to ChatGPT or Claude (I am!). If users opt for paid subscriptions to LLMs instead of free, ad-supported search, fine, but Google needs to be in that game and to get them to use Gemini rather than the competitors. For users who won't pay for a subscription, I assume that ad-supported LLM usage will become a thing, and Google clearly wants to get there first, or at least early enough. But right now they don't actually have the capacity and LLM usage is too expensive for an ad-supported model.
So... they need 1000X capacity, and they need it at something not too far above current OPEX costs. If it requires massive CAPEX, that's less problematic as long as it can be funded from revenues (including future revenues), and in fact it's actually good for Google if massive CAPEX is required, because it helps to build their moat, protecting them from competition by other companies that don't have the same resources. But OPEX can't be 1000X, it probably can't even be 10X.