People aren't going to get more hours in the day. So if you make travel slower, people will be less able to travel. If you want to talk about Americans vacationing to see Europe, you'd eat up a weeks or a month of time just in travel, making it impossible for everyone who wasn't independently wealthy. "Good!" is one response, but not one I think most people want to embrace. That's less "culture" and more denying people the travel and convenience they want. You're effectively denying any Americans who have to work for a living the chance for long-distance travel.