Obviously, Google makes money showing ads during search. But they have finally bit the bullet and starting tarpitting users in search in order to show more ads.
A quick, useful, and accurate search means that you're on their site for the least amount of time, perhaps mere seconds. That's not what's best for revenue growth.
PS: Go try Kagi and be reminded what good clean search results look like. I use it because my time has value. It's very good.