I was one of the unschoolers whose 7 year old didn't read! He wasn't ready or interested and to push and push for nothing except tears and anguish would have been awful for all involved. I admit to being quite worried about him and definitely was questioning our decision to unschool, after the first child taught himself to read at three, but he picked up reading when he was 8. And I say "picked up reading" because when he was ready, he simply picked up one of the books in his room and read it! We had been reading to him every day of his life and despite his seeming disinterest, he'd been paying attention. He certainly made mistakes along the way and we were there to help with pronunciation and sounding out the bigger words, but there was no struggle as there would have been if we'd tried to force the issue when he wasn't ready. He's still doesn't read much, it's just not something he finds the same pleasure in that his brother does. He reads at a college level, but it's not a passion. We're all individuals and that is something that public school doesn't acknowledge or tolerate (in my experience).
My eldest was so damaged by his 4 years in public school where he was not allowed to learn anything new, only allowed to "learn" the curriculum being taught that year, that he completely refused to study math or writing for 7 years. He was forced in school to do page after page, daily, of addition and subtraction that he knew before he was 2. They knew (he showed them) that he entered school (K) ready for 5th grade math and they refused to make any accommodation at all, until third grade (four years of misery). They punished him for wanting to learn. He was finally advanced two grades, but since that didn't address his pace of learning it became obvious that school was simply not going to work for him. While it was sometimes very stressful to just trust that he would eventually want to learn math again and that someday he'd embrace writing, we continued to allow him to pursue the subjects that really interested him. He taught himself what he needed to get into algebra when he began college at sixteen and chose a college that requires every student to write and defend a thesis to graduate!
I think the biggest thing we learned through home schooling is that learning is 24/7. It's not a separate part of life. It's not something you do on certain days or only from 8-3, it's ongoing and kids are soaking up everything all day and their brains continue to process while they sleep. We provided a rich learning environment at home and he was out in the community almost every day experiencing life and learning from all sorts of different people. He was not locked away at home with us, nor locked away in a school setting with only his same age "peers".
I totally support the idea of public schooling, but the execution is sorely lacking for so many.