Speaking for myself, I couldn't afford to go to the movies when I was in college, much less go overseas. However, once you're out of college and making decent money it doesn't take long to build up enough savings for a nice trip now and then. That's assuming you don't spend everything you make like a lot of people do.
There are also ways to travel cheaply. Couchsurfing might be OK for some, but that's not my cup of tea. I have enjoyed staying in hostels though. In Europe I've stayed nightly for as little as £6 in the British Isles, €7 in Europe, and $1.50 in southeast Asia. Believe it or not, I could have stayed even cheaper if I'd lowered my standards.
I saw one place in Laos where I could have stayed for 60 cents a night.
Finding cheap places to eat (or fixing your own food) is also pretty easy.
So really, the only expensive part about my travel is the plane ticket to get there.