I'm not sure whether those other "cities around the world" are a fair comparison. Install and operating expenses for fiber are dominated by labor costs, and skilled labor in the U.S. is expensive. The median adjusted household income in the U.S. is 90% higher than in Spain, and 40% higher than in France. That's why I used London and Zurich as points of reference, rather than say Barcelona (where, as you point out, you can get gigabit for under $45/month).