But one of the early points is "why is everything so gray instead of colorful?" Which is easy to answer -- when all your cars and buildings are super-colorful, they clash. They become garish and ugly and screaming for attention. Thank god we've moved to more neutral tones that actually tend to go together and recede into the background... so that we can use accent colors instead! If someone chooses to wear an attractive bright red or yellow top, let the accent be on them as a person, rather than their surroundings.
But otherwise, the answer to most of the rest of the essay is: economics. New construction (and furniture) looks the way it does because it's the cheapest to put together in terms of initial cost and maintenance for the building's desired lifespan.