It can be done, but it tales a lot of streams of income. I watch several YouTuber’s that travel and I have an idea of what they earn, all are couples so that they can divide the work up, but there is no way that they work a 4-hour work week. All have sponsors/endorsements; these take a while to earn credibility. Many also have Patreaon, which is basically people that pay them a regular monthly amount of money, and this can be a significant amount if they have hundreds of Patreons. Many also sell the skills that they have accumulated over the years as bloggers or Vloggers, and do other freelancing as well.
I myself know how long it can take to do post production on a fairly simple YouTube video, a 20 minute video can take a couple of full days post production work, work that must be done to meet the quality demands of a channel that has 100,000k+ followers.
There is a ton of planning that must happen before you even start your next entry, most of this stuff does not happen spontaneously like many outsiders think it does.
Lastly you have to know marketing and key word, hashtag research, and stay at the top of the various social media algorithms, that are always changing, this alone is almost a full-time job. If you don’t stay on top of this you quickly find your views and subscribers dropping precipitously.