I think I did a calculation a few years ago that there is only an acre or two of land on Earth for every single person. When you factor in the acreage that is currently liveable and is actually purchasable, you get a number close to 1/16th acre I imagine.
Having that amount of land allows one to have a ton of different hobbies and activities available that are really not possible in an urban environment. Want to go shoot guns or fireworks? No problem. Want a huge dirt trail with jumps for an ATV or dirt bike? Go ahead! Having that amount of land can also be great if you have a large family with many children as it acts as a safe-place for outdoor play. Although I didn't grow up on that much land, I grew up in a remote area with a ton of forests and being able to freely play tag or go hiking in the woods with my friends were some of greatest times in my entire life. Bow living in the city for work, I dream of the day that I can retire onto a property with a large acreage, I get the rationality.
I don't think universalism necessarily applies to lot sizes. Different people are willing/able to take different trade-offs. In exchange for a large lot, in a tranquil environment, I get few job opportunities without a long commute, poor telecoms coverage, a 30-45 minute drive to big box stores, limited diversity, people complaing about all the new residents moving from where I moved, etc. I don't think most people would make these choices, which is fine -- if more people chose to live here, maybe I'd want to live somewhere else.
As another poster mentioned, it's about the trade-offs. Cities have a lot of advantages that, for most, make it the ideal place to live.