What they fail to realise is that the reason they get paid so little is because of how many people can do that job. If your teacher just decided to quit one day, just walk out of the classroom, garunteed by the end of the day they will at least have a temporary replacement, and within a month probably a new permanant teacher. Supply and demand, the more there is of it, the lower its price.
(assuming the strike is about pay, I am too lazy to check the link)