alt Hacker NewsGoogle was not profitable until they rolled out ads, either.
The scope of use of AI assistants in people's lives are significantly higher than google search, imo. People use it in far more scenarios already than just information retrieval. That's why some are betting there's a chance it's more valuable than present-day google search.
IIRC Google had no monetization at all until ads. Even then the cost of providing search with ads is orders of magnitude lower compared to running LLMs.