Yes, there are, the common term is perpetual traveller (PT). I've done this myself, living out of a rollaboard suitcase for a year and half, although I wasn't exactly a full-fledged PT since I was notionally both resident and paying taxes in Singapore (not a high-tax country, mind you).
Most PTs who are in it for the long haul are either self-supportingly wealthy (have "fuck you money", in the charming term of the art), or are consultant/self-employed types in careers that let them work remotely from anywhere (online businesses, very specialized IT skillsets, financial traders, etc). Pseudo-PTs, like myself at the time, had jobs that required extensive travel to customer sites and where the employer was paying for accommodation and expenses; in my case, I designed and deployed SMS gateways, with a typical project lasting anywhere from 3 months to a year. (Have you ever gotten one of those "Welcome to Foophone!" SMSes when you landed in a new country? My invisible digital fingerprints are probably on that message.) Once I realized that it made no sense for me to pay rent on an apartment I was staying at maybe 4 nights a month, I dumped my stuff in a friend's spare room and rented hotels when I returned "home" once every few weeks, which still came out way cheaper and meant I never had to clean the toilet myself (woohoo!). Doing the vast majority of my travel in Asia, where eating out is cheaper than cooking at home, also helped quite a bit.
In both cases, though, the key is that you're not "managing to find jobs" along the way, but that you already have a job or valuable skillset that is valued enough that you can get paid at first-world rates even when traveling in third-world countries. Most answers over at the other "long term travel on the cheap" question aren't about PTs though, but what I'd call "self-sustaining travel", where the goal is to earn just enough to keep your head above the water and keep moving, and this is mostly done by menial jobs (fruit-picking etc). This is all good fun for a while when you're young, but most people can't realistically do this for their entire life. There are exceptions, some of whom are among the most interesting people I know, eg. one acquaintance who drives a charter bus in Finland for half the year (cash payments only, no taxes) and then travels around the world by hitching, catching rides on freighters etc until the money runs out, but they've also chosen not to have a family or savings.