Simple - there are many reasons not the least being quality of education.
We sent our children to a public state school [one of the best in the area] and then to a private high school. Suffice to say, the differences were chalk and cheese. A focus on excellence rather than mediocrity, a focus on aspiration instead of "close enough is good enough", a focus on developing teenagers into fine young adult, not just mind-numbing cliches like "caring, sharing and learning together" or lessons on inclusion and diversity.
The best investment my wife and I have ever made and worth every $$.
