My DH doesn't really get it either. And it's hard to when you're in your own bubble. I never got it until my oldest was 6+. And it's not really important for us since we're homeschooling. This fall, we started homeschooling my 5 year old. We never did anything with her academic with her before fall as DH well knows. But she is whipping through material as fast as we give it to her and I've put him in charge of ordering some curriculum for her. He's piecing it together.
It's funny - when people ask me why we homeschool I might say school wasn't a great fit for DS and elaborate if asked. We live in a high GT area and I'm surprised how many people get it immediately.
When people ask DH why we homeschool, he responds because I want to. LOL - I guess that's an easy and somewhat accurate answer. But it surely wasn't our initial plan. Our kid did attend 2 years of PS. Probably about 1 year too many for him.