Yup, many of the folks responding are glossing over this line in my OP:
> Had they already experienced everything good there is to experience in this one lifetime that they were so bored of it that they would prefer to work instead?
I'm telling it from my perspective; and travel means different things to different people. Sightseeing? People watching? Cultural immersion? History? Exploring the outdoors? More generally, I look at it as "experience this Earth while you're here".