their job

I believe it depends on the country's govt and it's demand and supply. If demand is there, the pay will go up. If the govt is emphasizing on good education, they'll pay well to attract good teachers. In Singapore, I would say the pay is not bad... Maybe you want to come here to teach. But, the demands to be a teacher is high... Probably that's why they pay well. To squeeze the life out of you.

I suspect that the real answer in the US (and even more so in less wealthy countries) is that society simply can't afford to pay us what we are truly worth. It's a lot like day care services-for child care workers to earn a decent wage, they'd have to charge far more than families could afford for their services. And I think society dramatically undervalues teaching-If I had a nickel for the people who've told me I was "wasting my life" as a special ed teacher, I'd be a rich woman!

well,for teachers ,there earnings exsist big gaps in China now. Most of teachers especially work in countryside or town,their earning are almost the lowest,even lower than teacher teach in the same city,but some teacher who teach music,dancing,children english are making big profit from different kinds of extracurricular activities,such as interest groups,they can ask kids' parents for extra money.