Thanks for your thoughts and observations.
I may be one of these “simply sight readers”. I supposedly taught myself to read at an alarmingly, insufferably young age. I have no memory of learning to read whatsoever, only the before and the after. We had a complete set of McGuffey readers lying around (thanks for mentioning these, brought back memories!) but by the time I was looking at them I could already sight read and thought the phonics stuff seemed somewhere between too obvious, too detailed, and too boring. The first word my parents noticed me identify was a pretty bizarre proper noun and not phonics-friendly at all.
My best guess is that since everyone in my house could read, and clearly enjoyed it, and did it all the time, I had plenty of readers to study in action and lots of motivation to watch them. Kind of like when you see a little crawling toddler staring at an older kid who’s running, totally stunned with jealousy... calculating, calculating... From before I could read, I remember asking “what does that say?” a lot. Making them read me sentences on demand. I’m a very fortunate person.
I’d be interested to know how network effects helped your six children and many siblings, on top of the dedicated instruction. Seeing you reading casually, knowing you enjoyed it, seeing their peers do it.