That's only what happens in the bougie suburbs. Literal teams of professional staff making putting greens in front of stately homes, because keeping grass that thick and low takes a lot of regular work. Most places that aren't a desert or Mediterranean climate in the US don't need their lawns watered, rain is frequent enough, and grass might only need to be cut 1-2 times a week if that, depending on the rains. Overall, even in places that need sprinklers like CA, sprinkler systems don't use much water relative to other strains on the water system such as industry. It might be foolhardy to grow a lawn where the heat is regularly exceeding 100*, however, because you will practically have to water multiple times a day to keep up with the hot ground baking out the water.