You make excellent points. I went to a dentist last year who wanted to extract my root canaled teeth (5 of them). I said "no thank you."
Yes, vitamin D is very important. Vitamin C, a mineral-rich diet, and oil pulling will also help keep the jawbone and immune system strong, and infection at bay.
Found this at a site for denture wearers (I'm not one)from someone recounting her process for getting them. She said of the root canal extractions:
"When he started to pull out the back teeth, they broke off. He cut the gum to find out that the teeth had started to grow around the bone to make up for no roots. He ended up cutting my gums all around to make sure there no pieces of tooth left; he was having to chisel them out."
Sounds like there was still some life in those "dead" teeth!