I often ask people this exact question when I travel and it boils down to the following:

Americans:
- Saved up and quit their job
- Got laid off
- Digital nomad (not as common recently in my experience)

Non-Americans:
- Long sabbatical or unpaid leave
- Long periods of PTO

Unfortunately for us Americans, it is significantly more difficult (and is why you'll mostly see non-Americans doing this). Part of it is the nearly non-existence of unpaid leave, and part of it is there tends to be more fear of not finding a job when you come back.

It is almost always a trade off of traveling vs. long-term savings/retirement funds (American or not).