There are lots of ways which have worked for different children.
Rather than answering the question you asked, first I'll pose you a different one: why do we care so much about children's reading that this one skill seems to dominate early years education, and are we right to be so concerned about it?
I don't for a moment argue that literacy is unimportant in our society. It is key, absolutely. A functionally illiterate adult is bound to have a very hard time coping in life. However, basic literacy is a skill which nearly everyone can manage to acquire, so why actually worry about it? Why take active steps to promote it at an early age? I mean, did you worry much about whether your son might prove quite unable to walk? That too was a possibility, and growing to adulthood unable to walk would have affected his life in many ways. But you probably trusted that this would come to him in its own time, as it does to most children.
IMO the answer to why reading and writing dominate school education is because the school system itself relies so heavily on that particular skill. The very high ratio of children to adults at school means that reading is a key method of instruction there. Similarly, children are given written tests to assess what they know because the teachers are unable to spend enough time with them individually to observe what they know or discover what they know in conversation.
And then the resultant self-esteem problem rears its head. Schoolchildren know they are expected to learn to read young. This matters above all else in their education. No wonder that they often feel they are stupid if they can't do it, and angry if they don't yet want to do it. As they get older, if they still can't read, the fear of failure sometimes causes them to switch off and stop trying.
By contrast, a home educated child doesn't need to be able to read well from an early age in order to get a good education, nor does he have to write fluently so that educators know whether he understands the material. They learn from conversation, from doing things, from having parents read to them, from watching documentaries. Their parents have no performance targets and don't really need to test them, but if we do want to know whether they understand, we can just talk to them and watch them. So there's no time pressure on us.
And with that pressure off, reading and writing can be tackled at an age when the child is very likely to be developmentally ready for it, and when he has discovered his own motivation to do it. Ensuring that both of those factors are in place makes it much much much easier. You probably weren't dragging your unwilling eleven month old baby around on his legs trying to make him walk when he wasn't interested and quite possibly couldn't have done it even if he wanted to. The fact that SOME babies can walk at that age wouldn't have swayed you, nor would the fact that with hothousing, your baby's progress might have been accelerated a bit. You knew that in the long run, it wouldn't matter whether he first walked before or after his first birthday. When he wanted to walk and was ready, he applied all of his determination and you couldn't have stopped him picking up that skill if you'd tried.
Peter Gray has some fascinating and reassuring observations on home educated children who learn to read in their own time: www.psychologytoday.com/us/blog/freedom-learn/201002/children-teach-themselves-read . I think if you spend enough time around the many home educated kids who have followed vastly differing paths to reading competency, you'll start to feel more relaxed about the reading/writing bugbear. Ask the parents of older children, as you are doing here, how it worked out. You can also read home ed blogs.
The school perspective on reading - the earlier the better, and definitely by the late primary years - tends to instill a greater panic in us than it needs to. I doubt any of us HE parents are completely immune to it. But ultimately, we do have the option of turning our backs on that system, taking inspiration from the example of other home educated kids and most importantly from our own child.