Americans fetishize wealth and often discriminate based on signals of wealth from others, so it makes perfect sense that we fetishize a social signal of wealth that cannot be faked effectively. That's why we still have lawns, even when a third (or whatever) of our drinking water gets poured into them each year, because it's more important to signal wealth here than it is to conserve water. Unfortunately, we also have lawns because they are a sign of "cleanliness", as our racists often label their desire to exclude non-whites, and they too prioritize exclusion over conservation.

In the 1950s, when perfect lawn 'suddenly' became popular (as per the article), both wealthy Americans and racist Americans (there's a lot of overlap) moving to and driving the creation of suburbs were trying to find ways to exclude both poor people and non-white people. This was implemented more and less blatantly to varying degrees, and lawns are one outcome of that exclusionary desire. Wealthy whites realized that lawns were a perfect signal of wealth, and racist whites realized that lawns were a reliable and deniable signal of "cleanliness", which is code for "whiteness". They both enforced those signals with codes and laws (and later HOAs) that require a tidily-kept lawn, in order to exclude anyone unable to afford the time and money to maintain one, and both groups benefited from each other's efforts.

Those laws continue to be enforced today in many neighborhoods, against people without the resources to maintain a lawn, and against people who voluntarily choose not to. That's why police are called on someone who grows a garden in their front yard: if anyone can just not grow a lawn, then the exclusionary groups think the neighborhood will decline into poverty and crime, because it will no longer be restricted to wealthy and/or white residents only.