A good massage school will teach you good technique and good body mechanics so you don't burn out quickly. Those who do burn out in a matter of a few years overwork themselves and use poor ergonomics. It's not the career field, it's the people in it making poor choices.
As for giving up and leaving the field, that's also a poor choice. I trained and now work in a decent-sized metro area and the help-wanted board was always full of notices while I was in school (which was during the brunt of the recession, I might add) - one of which I answered and landed the job I have now, which keeps me busy enough to make ends meet, even during the slow season. If therapists can't find work, they either aren't looking hard enough or they aren't doing a good enough job to hang on to regular clients. Especially in a major city like Seattle, finding work shouldn't be a problem. If it is, it's a personal one.
If you really want to know the climate of the job market and its potential in your area, ask around in your area. Visit a couple of schools and see what they have to tell you about former students' success rates in job placement and so on. Ask around with people you know and see if they know anyone locally who is currently in massage or esthetics and would be willing to talk to you about it.