I have taught at private language schools, public elementary, junior high, and senior high schools, and universities in Japan. They roughly rank in that order in terms of prestige, financial remuneration, and ease of getting a job.
A job at an eikaiwa school is the easiest to get, the worst paid, and has the least amount of prestige (want proof? See how estate agents treat you). Working in public schools is better paid, more challenging to get, and is perceived as being higher by society (some of the dwindling prestige of public school teachers rubs off). Finally, a university position tends to pay rather well, involves jumping through various hoops (publications, experience teaching at the tertiary level, Japanese ability, postgraduate qualifications), and confers a reasonably high status (varying somewhat according to the institution in question).
Seemingly illogically, the actual amount of skill required to do the job well seems to run in the opposite direction. I would say, based on my experience, teaching at an eikaiwa, where you will probably have students ranging from 3 to 70 years old, and classes that run the gamut from 40 kindergarteners to one sleep-deprived businessman or a group of senior citizens, requires the most skill to perform well.
Teaching in public schools can provide discipline challenges, but the range of teaching situations is less varied and the curriculum provides a framework that reduces the amount of material teachers need to master.
Finally, teachers at the university level probably need the least amount of teaching skill to get by: their students are selected for academic potential (yes, even at the worst universities) and teachers tend to have the freedom to decide on the content of their classes. University teachers are pretty much encouraged to teach to their strengths, and can get away with teaching a narrow range of material if they so choose.
So why are the positions that need the most skilled teachers the worst paid?
You can see something similar even within public schools: kindergarten teachers are the least well paid and regarded, followed by elementary school teachers, then junior high school teachers, and finally high school teachers. However, if we look at the potential impact that teachers can have upon their charges, the early years are far more influential. Children who have excellent teachers during the first years of their schooling, then mediocre ones later, are likely to do much better than children in the opposite situation. Why then does society seem to have its priorities so badly skewed?
Is this fixable? Can you imagine a world where kindergarten teachers are given the pay, training, and status the importance of their job deserves? Will the cushiness of university positions be reflected in salaries?
As always, comments very much appreciated below.