That's not the point and that's not quite what I meant by 'navigate.'
Comparing Paris, London and Rome to New York, Los Angeles and Chicago is moronic. The former three cities are in different countries--they use different languages and have very different, if often-interrelated histories. Chicago and Los Angeles have always been within the United States. New York predates Independence but didn't begin developing into what is now until after the Industrial Revolution.
Most American cities did not become densely populated until after the Industrial Revolution and, in many cases, the advent of the automobile. Considering the rapid pace of urbanization in the United States, cities have followed and implemented similar urban planning strategies, with a handful of noteworthy exceptions. They've grown under the same government since they were founded--a government which has changed its course and aim but retained a long mantra of 'nation first.'
I will not deny that moving from one city to another can be challenging, especially for people who haven't lived abroad. But if I may repeat myself: it is disingenuous to suggest that the cultural differences between American cities are comparable to those between countries. There is a reason why people tend to be preoccupied with international travel, and it is that going abroad presents drastically different experiences (in terms of culture, geography, history and socialization) that cannot be had at home.
That aside, a monoglot English speaker cannot 'navigate' Paris or Rome in the same way they could Los Angeles or Chicago. Not knowing how to speak French in Paris means that innumerable doors to culture, to history and to socialization are off-limits until one becomes proficient in French.
Can you go to Rome, 'navigate' the streets, stay in a hostel, rent an apartment or even get a job without knowing Italian? Yes, you could. But you'd be incapable of relating to the city at a fundamental level.