I think the tone of the article, and especially the graphic, is a little misleading. An 80/20% allocation of turf is certainly sufficient. This is not requiring people to dig up all of their lawn except for a 500 sf square. And if 500 sf fits 8 Mini Coopers, how many Expeditions could fit?
You could do some really neat stuff with 500 sf of lawn which would be far more interesting to a child or a dog than a flat 10,000 sf flat expanse of turf. Or you could walk your kid or take your dog to the park…
I wish I could read the comments following an article like that and be entertained, but they usually just make me sick.