Many lawns in the US do use grass native to that part of the US. Not all, but many. However grass goes dormant when it doesn't rain for a couple weeks and people don't like that brown look so they water even though the grass (either native or imported) doesn't need it. Likewise people don't like flowers and other weeds and so they apply a lot of chemicals to the lawn - but the grass doesn't need them.
TL;DR: lawns in the US do not need any resources. It is "perfect lawns" that need a lot of resources.
TL;DR: lawns in the US do not need any resources. It is "perfect lawns" that need a lot of resources.