Google used to not have any ads for many years while they got market share. Then only small ads off to the side. Eventually the ads moved inline and were half the results, etc.

AI summary seems like the same play, even if it hurts their current ad business some. After all why search for stuff when a chatbot can just tell you? Makes sense they'd view it as an existential crisis and push their AI.

Google will be well positioned when ads start being added to AI for most users.