For Americans who don't travel internationally what stops you from traveling?

Some background first for why I'm asking: I've traveled extensively since I graduated college in 2015. I've been to 35 countries so far and lived abroad in 4 of them. However being American and getting English and Spanish certified I've worked as an elementary school teacher which is a lot easier to find jobs in. This puts me in a very unique position to see how other cultures function naturally. I've spent a couple of years in Japan, Chile, Mexico, and Vietnam where I've worked in elementary schools. This has allowed me to see how regular people live their lives and get a direct comparison. By far the largest differences I've seen are in travel habits.<br><br>The 4 countries I've lived in all have American fantasies, particularly Japan. By far the biggest difference is that Americans don't seem to travel internationally at all. I watched a video of a teacher showing her American school a map of the world and pointing out where she lived while she was abroad. She asked the kids to identify North America, then the United States, then the state she was in, then the city, etc. It was very eye opening because my current school in Vietnam is very big on education. In Vietnam we did the opposite and started local. Each grade they get a bigger view of where they live in the world. They start with their neighborhood, then the city, then province, then country, south east Asia, and then the world. Most kids in my current school have never left the country but a lot have left the province. In Japan kids are also encouraged to travel. Traveling domestically in Chile and Mexico is also common but less than in Japan and Vietnam.<br><br>tl;dr: I've lived in Japan, Chile, Mexico, and Vietnam for a couple of years minimum. By far the biggest difference is that Americans seem not to travel outside of the country. Why is this?