Where, if I may ask, did they live, then?
Are you asking me? (It's clearer if you reply with quote
) They were travelling, so they lived where their travels took them, usually doing air-bnb or house-sitting if they can get it. Or a group will start off travelling together and split housing for a few months, make new friends and then move on with them. (As I said, it's more gap-year or -two or -three than lifelong.) The writers among them tend to get articles published here and there - a couple of them have come back with books, but the travels seem to only form part of that story.
The one who's been at it longest is now in her early 30s - she's been living nomadically in places that would seem quite challenging for a single young woman (Afghanistan, Pakistan, various countries in Africa) - since her late teens. She tends to stay there till she runs out of money, comes back home and couch-surf with friends (she's delightful company with excellent stories), working hard at low-level jobs till she's got enough saved - and then she hits the road again. She does write about her travels, and has sold some pieces, but that's not why she writes (or travels). She's an excellent photographer and a very good writer, but she doesn't bring in anything like enough to fund her travels that way.
ETA: Just going back to your first question - yes it is possible to write without having money behind you, but making a living as a writer is extraordinarily difficult. Which doesn't mean anyone should give up writing ever, just that we all need to know to take care of other things (healthcare, primarily) as well. It's all a lot easier for kids who have a couple of years grace, and a bit of money behind them.