Most parents want their children to grow up to be smart, successful, caring adults. Teaching the skills that contribute to these characteristics starts early on. You teach babies to share. You teach your toddler empathy. You teach your preschooler to respect others. You teach your kindergartner to read.
When skills like these are present and emphasized, a child grows up to flourish in these areas. You would never wait until your child is a teen to teach addition or listening skills, so why do so many schools wait so long to introduce foreign language classes and teach children about having a global mindset?