It doesn't cost more to paint a beautiful painting than one that's not beautiful. I think architects give the excuse that beauty costs more in the same way that car designers give the excuse that beauty is less aerodynamic. We're not racing in NASCAR. Let's suspend performance requirements just to call their bluff. We should call the architect's bluff by giving them a billion dollars. Now design a beautiful building. Once we eliminate their excuses, we can prove that quality isn't a tradeoff. Lack of quality represents a decline in progress. Progress doesn't mean accepting lower standards.
High-quality buildings only cost more if nobody knows how to do it. If people don't know how to do it, then it is infinitely expensive. If only one person in the world knows how to do it, then it is expensive to hire him because he can't be everywhere at once. If we gave a good architect and a bad architect the same budget, the buildings would cost the same, so it's not a question of money. The difference is that the novice architect doesn't know how to make a good building, whereas the better architect does. Prior cultures were able to build beautiful cities with very few resources. They had a local building culture that everybody knew.
A good architect can design a nice-looking building given most circumstances. Even if the materials, construction methods, and codes aren't ideal, the talented architect will know how to prioritize what is important. Society should make the path of least resistance the correct one, so quality isn't the exception to the rule. We shouldn't have to fight bureaucracy when we're doing the right thing. If we built for ourselves, like was common, buildings would not only be higher-quality, but they would be less expensive because we wouldn't need to hire an architect.