Doesn't arguing about how much he spends each year kind of miss the point? I doubt he would travel like he does without the blog, but I also doubt he would be any less happy. Including travel business expenses in his personal spending doesn't make much sense to me.
He is simply saying he has optimized his spending so that around 25k +15k housing feels ridiculously rich to him.
His costs are so low because he has optimized everything, and he has a very aggressive (crazy) approach to risk management (minimal insurance, no dentist, etc.) He is living a lifestyle of someone spending much more simply by being efficient. That is how message.
Personally I would not do it, and cannot do it. I would not feel comfortable with so little insurance, and I simply have more things in my life that cost money, but he shows me what is possible.