Lack of representation means politicians care about children only to the extent required to get a parental vote. Take the lot of a child in my country (Australia):
* Childcare is a political football. The primary aim of the system is to allow parents to work rather then provide the best environment for children. Excellence is a result of individual centres rather than a product of the system.
* Children are taxed at 45%. If you want to prevent parents from putting investments in children's names, write laws about parents exploiting their children rather than penalising the child.
* Schools are a political football, with politicians debating funding, testing regimes and curriculum and the children nowhere to be heard.
* Old men (and a few old women) are making decisions that will affect the world long after they are dead. The currently disenfranchised children are the ones who are going to be stuck with the mess.
Adults wouldn't (and don't) put up with it, so why should children?