I would agree that not many can make it big, just like in all entertainment genres. Most will have to do something more traditional to make a living, because they just didn't have that one extra ingredient. I would also agree that some trying to live hand to mouth, like a beach bum, is not a responsible endeavor. This channel is the top of the pack and it's fairly easy to estimate they take in several hundred thousand dollars per year in revenue. It may be pushing $500k by now. Plenty to fund a very well to do financial household, even after expenses.
Anyone at the top of their field deserves to get paid. I was curious so did a bit of research on Patreon averages from their site and other travel youtubers.
La Vagabonde has 3500 Patreons with average donation of $5. Typical reduction rates after the first video each month is 100% ($17,500) for the first video, 80% ($14,000) second, 65% ($11,375) third and 50% ($8,750)for the forth video of the month. That is $619,500 a year from Patreons.
They had 6.555 million video views in the past 30 days. The numbers from Youtube are $3-5 per 1000 views. Take the lowest of this at $19,650 a month and that is $235,800 a year.
Right there is $855,300 a year not including donations from Paypal, and sponsors like Audible.
What a business they are running! Pretty cool to see what's possible these days with a laptop, camera, good looks and a good story.