For us, afterschooling and extracurricular activities are the main mode of learning. My kids are used to it. We certainly wish that they could learn what they need to learn at school, and do other things at home, but this hasn't worked. My DS had a reasonable K and 1st grade (the teachers were really good at differentiation). But since we moved to a new district (supposedly a very good one, too) things just never worked out in public schools. We have no gifted program and in-class enrichment is way below my kids' real levels. The local gifted, private schools are also not at my kids' levels. So it kind of just evolved into the situation where the kids go and have some fun with friends at school, try not to get in trouble with the teachers, and the majority of learning happens at home.
This will change soon, though. Our district finally started allowing students to take above-grade-level courses online for acceleration. I think DD will sign up as soon as she is old enough. DS will go to a HS with a strong academic focus and there will be lots of choices within and outside of school.
Afterschooling is not ideal for us but we just didn't have better choices.
