As for how my DD's intrinsic personality has been affected by the kind of conditioning described in the OP...
She displayed something that looked a lot like shyness in public school, because of the things that I'd mentioned before. She was being highly selective, and the other kids were simply not her peers. She also had negative experiences with a couple of her teachers, and that dynamic affected her ability to form friendships with classmates. But, get her outside of those issues, and she is who she is. When we're talking about intro/extroversion, we're talking about an intrinsic personality property, after all.
I underwent some things similar to my DD's experience, for a far longer time, and I can't say it affected my degree of extroversion, either. I am who I am.
