In some countries, law protect sabatical leaves, like you can take a 12 month leave and your employer has to give you back your job.
That said, many people travel for shorter time like 4-6 weeks and just use their regular holyday to do so…
Then there is the whole part of kids who use daddy’s money, and the the other who use stuff like Work Holyday visa allowing them to work part-time in a foreign country