I do see your point, and agree to a certain extent. Having spent some time in south-east asia, I have experienced first hand how cheap life can be compared to what I'm used to (a factor of 10, for a comparable lifestyle). In fact at one point I would consider that I pretty much ran out of money but still managed to get by.
However, I still see this type of travelling as a luxury. I would not fly off to another country for 6 months or longer, without a significant amount of savings.
Not everyone can necessarily do a bit of freelance work when they are abroad. As a former freelancer who who's spent several years now working full-time in an office, I have lost a lot of my freelance network of clients and contacts. Furthermore, if we're looking outside of the Hacker News community, not everyone has a skill that can be as easily marketable from a distance.
Trying to establish a freelance network back in your native country, once you're abroad could be an option for me, although not one I would rely on for my survival. I would also not rely on acquiring work visas, either. Especially if I couldn't prove to the relevant authorities that I had enough existing savings to not be a burden.
So unless you're a person in a particular situation in life, with a specific skill set, you will still be spending a reasonable amount of money during your months or years abroad. Add to that flights, insurance (maybe you're not too keen on cheap surgery in a third world country), vaccinations, the loss of maybe a few years contributions to your retirement savings, the cost of reintegrating yourself into your country when you return. Things get expensive. Although I previously did not think so, I would now definitely consider long-term travelling (with the intent of returning) a luxury.
Edit: That's not to say it's not a good idea. Or that it's impossible. As far as luxuries go, it's a very good one to go for.