Ask Lemmygrad

In the past a lawn was a status symbol. It showed that you have enough disposable wealth to maintain something that is purely decorative and serves no practical purpose. (And by the way, keeping a lawn is actually quite resource intensive, it takes a lot of water compared to other vegetation.)

Whereas traditionally, growing fruits, vegetables and useful herbs was seen as something that poor people did out of necessity. This is an attitude that originates with the British aristocracy and was then passed on to the culture of the American upper and upper-middle classes.

Nowadays this has somewhat reversed, and as more middle class people have adopted lawns, the wealthy needed to have new status symbols to differentiate themselves from the masses, and so they have started owning orchards, vineyards and like.