yeah i don’t mean to say no lawn should ever exist, just that we seem to put an absurd amount of our resources into them.

if a home costs $1m, and 50% of it is a lawn, shouldn’t the home owner start wondering why they need all that empty space? 

it doesn’t have to be a garden that replaces the lawn either, maybe it’s just an ADU or extra room added to the house.

culture

Why do we all have lawns?

The lawn hate is so trendy but they are fantastic. If you own a bit of land then a lawn is a very useful thing - kids, dogs, sports, etc all benefit. If you don't mow you will end up with pasture, which can be OK but still needs a lot of work to keep free of things like burdock, wild parsnip and other undesirables taking over. If you do nothing, you will end up with land that is truly not of any use and looks bad. 

If you live in the burbs and only have a postage stamp then maybe it's a waste but the idea that your land should be productive is a strange one. You as the owner make it productive with lots of effort so a trade-off is made. If you own a couple acres or more you likely will not want it all to be "productive" but will want it attractive and easy to keep that way. 