Usually the only time Americans can take long vacations is between jobs. I wonder how many actually change jobs just for this reason. I asked for 4 consecutive weeks off to travel Europe once at a previous employer (I had worked there 5 years with no more then a week and a half off) and they denied the request. So I found another job and made sure I had a 4 week break between the two.
It's interesting however--some folks take advantage of the flexibility, while others do not. Just about everyone in the R&D group travels frequently, and the CEO will often go dark for a month at a time, but others in the company don't take more than a week or two of their PTO each year.