It's also not buying new white things every few months, which is what some of my American friends do. Because when you only wear linen, you can't just go around replacing it all the time, now can you?
It's the WASHING MACHINES.
The standard Italian washing machine (like ours, which is 35 years old and the best washer I have ever used EVER) doesn't have a "hot," "warm," and "cold" setting, corresponding to the house's hot and cold water systems. Instead, you can set the exact temperature of the water, and the machine heats it for you - up to 194 degrees Fahrenheit (90 Celsius) - almost boiling.
Thus the absence of unsightly yellow armpit marks.
Thus the absence of that mysterious grey color that comes from New York City laundromats of which you would be ill-served to contemplate the precise origins.
Thus the convenient disinfection of all your clothes. Many Italians don't even wash their darks at lower than 60 degrees Celsius (140 degrees Fahrenheit), so they don't lose the disinfectant power of their washers.
Where are you on this one, Maytag??