Ads have been close enough to covering costs for conventional internet search that even though I'm clearly the product and not the customer the relationship has still generally worked. If AI makes the "searching" 50 times more expensive, though, that could shift the relationship pretty badly in a direction of "if you're not paying for this you're not getting honest results". Paying may not sufficient for honesty but it may be necessary.
Honest question. But anyone who wants to answer this and who looks at Google's income/profit/revenue and is bedazzled by the size, don't forget to divide out by the number of Google's customers and ponder what that means. The per-user numbers are the much more relevant numbers and much less likely to cause Large Number Syndrome.