Teaching English in Thailand is a good match for some people at some stages of life and maybe not a good match for the same or different people at different stages in life.
If someone is teaching English to mostly fund travel and live abroad for a few years, Thailand can be a great place for many reasons. So for younger individuals who want to gain some experience and do something “exciting” before setting down to a career, or for someone experiencing a mid-life crisis and wants to try something completely different, or for someone semi-retired and wanting to live in Thailand, teaching English in LOS might be a good choice if one is ok with the culture and ways of doing things in Thai schools.
Also for those who are looking for a fairly stress-free life and are not too worried about material possessions or career advancement, teaching English in Thailand long-term might be a viable option.
On the other hand, if someone is a professional and life-long English teacher, who wants to have a career (as opposed to a job) and support a family and so on, teaching in Thailand probably is not the best long-term path to achieving these goals. Because teaching English in Thailand helps some people achieve their personal objectives, that doesn’t imply it is a good choice for other individuals who have very different goals and/or at different stages in life.
I taught English in Thailand for a while. It was good at the time, but I realized that it was not the right long-term plan for me, so I moved on to attack other professional opportunities. I never regretted the choice to teach English in Thailand or the later choice to move on to other things. It was a good choice at a particular stage of my life but it would not be a good choice for where I am now, but who knows, I might return to teaching English in Thailand at some future stage of life when the goals will again be different than they are now.
Thinking in terms of teaching in Thailand in plain good or bad terms is probably a little too simplistic to be useful.