It really depends on a lot of factors. I just came back from 10 month overland travel of South America. It is cheap over there - much cheaper than back home most of the time. We saved with my girlfriend for couple of years, rented our house and went for it. On the road we met all kinds of people. A LOT of European retirees. You can live quiet the life over there with the couple thousand euro western European pensions. Some of them go for a few months each year, some have been traveling for years already. Lots of younger people just did what we did - saved for some time and then went for it. Average salary in countries like Bolivia, Peru, Colombia, Brazil, etc can be just a few hundred dollars a month, so not that hard to do better than that. It’s similar on other continents - Indonesia, Thailand, Vietnam in Asia; Kenya, Morocco, etc in Africa - popular destination with lower standards of living that makes them easy to travel to for longer. When you travel for weeks and months it also gets cheaper per day compared to when you go on a vacation for 7-10 days - you cook, you can find deals, you travel a lot - not just to the tourist hotspots and traps. Bali can be just as expensive as a western country, but the Indonesian country side is cheap as hell. Having an own house also helps immensely - you do not pay rent in the months and years prior to leaving and after that you collect rent.
Then there are of course people with inheritance, daddy money, trust funds, etc. In all my travels I have not met any yet. They do not tend to go on the longer trips usually.
You can pretty much forget about making it solely through vlogging, blogging and writing for magazines and websites. It can add something every now and the , but there are single digits few normal people that have made it work full time.
Gen Z++