The yard isn't necessarily there to be used in the way you mean. Often the yard is a buffer between you and your neighbor. Your noisy neighbor who smokes, swears, and plays the most disagreeable music at the highest volume late into the night. Any distance is helpful.
I don't mind city life for the most part, except for the whole thing with most apartment complexes being built of cardboard, which means that every single thing your upstairs neighbor and many of the things your adjacent neighbors are doing can be heard loud and clear, and this problem plagues even newer construction. And then you have people on the street yelling, vehicles modified to be as loud as possible driving by, etc.
If these buildings were properly soundproofed, in many ways I'd prefer living in the city, but as things stand the only people who get to enjoy that in cities are those at the tops of skyscrapers renting penthouse suites, all of whom reside in a plane of existence entirely separate from my own.
The number one thing I've enjoyed about suburb life, particularly as a remote worker, is how much more dramatically quiet it is, primarily thanks to not sharing a wall with anybody.
This. I see so many people say, build vertical, density. Then when 80% of the people explain that everyone is fucking noisy, the vertical people don't reply.
I live in a house with a large yard for the exact reason you point out :).
I do enjoy walking on the grass and taking care of some plants, but I didn't really need so much land if not to keep neighbours away (I used to live in an apartment where a neighbour made my life hell, never again).
My big problem with cities is the people.