Gemini is easily the single most popular LLM family used in the world, period.

As in, it probably has 90% of the market share. Possibly even 99%, going by number of prompts made.

This is not a “gotcha” kind of argumentative question, I am genuinely asking curiously: is the AI overview and AI lens thing really making Google lots of money?

It's true that Google is still very successful, but simply calling their AI a successful product misses the full picture. Their flagship product has always been and continues to be advertising, the AI overview is only there to pull people away from ChatGPT and, similar to ChatGPT itself, is not a product the vast majority of people would be interested in paying for - it exists only as a sort of loss leader to keep people looking at ads, and is not making any sort of profit on its own (quite the contrary, I imagine it's pretty expensive to run every query through an LLM, even if it's a small one.)

AI labs have long since realized that the only real path to direct profitability is coding, and in this, Google have indeed fallen behind.

You can, of course, argue that none of this matters as long as the whole is making a profit, but I think the distinction is important.