tl;dr: The tradition of a grass lawn is really harmful and clover lawns are much better.
Traditions are somewhat strange things. They often have their origins in some pretty peculiar circumstances. The reason why we have a best man at a wedding comes from having a trusted warrior with a sword to deal with things in case the ceremony went sideways. Bridesmaids existed to offer suitable distractions from ghosts and spirits, and worse case scenario, kidnapping. Nice, eh? Candles on birthday cakes date back to trying to replicate the moon in honor of Artemis. Pinky swears originate with the Yakuza, the Japanese mafia. Almost all of our traditions have some weird or unrelated purpose to what we do in today's society.
Sustainability involves adaptation, which is the antithesis of tradition. We cannot continue with many things that we seem to do without even considering why we do them. One of these is the American obsession with a grassy lawn. Homeowners strive to have yards that rival Augusta National and probably have no idea why they do it besides that is just what we do. We take care of our homes, and a nice looking yard is an important part of that. The origin of this odd obsession comes from medieval France and England where castles needed clear land to see invaders. It quickly evolved into an ostentatious display of wealth because some landowners were so rich that they didn't need to cultivate all of their land and could leave it relatively fallow. Not only did they not need to plow the land or plant on it, they could afford to invest labor into making it look splendid. To the best of my knowledge, there is no property in the US that requires castle defense techniques. Even without this threat, lawns full of various useless grasses exist everywhere.
Americans love their yards. We spend more money on lawn care than we do on foreign aid. It has been estimated that Americans spend almost 40,000,000 hours of their time a year on yardwork. That is over 4,480 years of effort. The average American adult spends about 9.6 minutes a day on yardwork. That is more time than we spend on homework/research (7.8), volunteering (7.8) or phone calls, mail, and email (6). There are 31.6 million acres of lawns that require 80 million people to tend to them. More than $76 billion a year is spent on lawncare in the US. All of this time and money spent on mimicking something that isn't even relevant in the modern world seems kinda ludicrous, no?
It only gets worse when we dig a little bit deeper. Lawns account for 10 times the amount of pesticides than land devoted to agribusiness per acre. The well-groomed lawn accounts for the deaths of 7 million birds a year. Honey bees are in dire straits, one of the reasons being pesticides. The phosphorus from yard fertilizer causes algae blooms in lakes, literally suffocating fish in low oxygen waters. Some dogs have died from swimming in algae infested lakes. It's estimated 30% of all the water used on the East Coast goes towards watering lawns. Is tradition a justifiable reason to expend this much in resources and cause this much consumption and damage?
Some of you will respond with a resounding "YES!" Ideally, I would be able to convince you that the best yard is one that resembles as closely as possible the natural habitat of where you live. Perhaps there is a compromise to be had. Why do you insist on planting grass? The reason is because you have been manipulated by companies into believing that any other plant is a weed, and weeds need to die. This is simply not the case. A "weed" that offers many of the same benefits of Kentucky bluegrass or Bermuda grass is clover. You would be honoring tradition by having a clover lawn, since most yards were clover until the 50s, when broadleaf herbicides killed anything that wasn't grass.
If you transition to a clover yard, you will find that it will require much less water. Hate mowing your yard? If you had a clover lawn, it would only need to be mowed sporadically. Despise brown spots? Clover is far hardier to drought than grass. Clover also requires no fertilizer at all. It's technically a legume, so it actually makes its own. Clover seed is also 1/8 the cost of grass seed and requires no aeration because it is also a living mulch. And if you are worried about the plight of bees in the US, take a guess whether bees prefer grass or clover.
You literally have almost no reason not to convert to a clover lawn, unless you host daily football games (because it gets damaged with repetitive trampling) or have someone with a deathly bee allergy. Otherwise, the facts are clear and the benefits are outstanding. In summary, while in many cases tradition and sustainability aren't the best of friends, mindfulness would love to buddy up with sustainability. We don't have to dispose of tradition, but we can find ways to reduce their harm and impact and we can honor another odd tradition, finding a four leaf clover. Trust me, we need all the luck we can get when tackling our sustainability challenges.