What is the main purpose of public schools?

I always remember one of my high school teacher​s who asked the class what is the main purpose of public school. His answer was to create a homogeneous workforce. This statement has always stuck with me because of its stark honesty. This was not how it always had been. We have aided and abetted the idea that training for a job is more important than developing imagination, creativity, and intelligence. We are all complicit in allowing our country to be turned into a work camp. This is possibly the core reason for a decline of the arts in our country along with a decline in our quality of life.

I just read this article on Huffington Post about a mother telling the school her daughter was done with homework! It was time to stop turning her kid into a workaholic.

I had previously read that in Finland homework is essentially banned. Yet, they have the highest PISA test scores (Program for International Student Assessment). More of their kids go on to college than here or in Europe. They spend less on their education system and spend less time educating their kids but get better results. There are several reasons for the huge success of their schools over ours, but the essence of it is that their society values the teachers by not overworking them, and their society values imagination, creativity, play, and intelligence over job training.