I feel the same way. Had my AvPD been diagnosed when I was already an outsider and loner back in school, it could have been treated and never ever gotten that extreme. As you said, personality traits aren't instantly curable. But people are able to change over a long period of time. You can't change the past, as unfortunate as it may be. It's important to conclude with your past, but don't focus too much on it to the point where it only makes you feel bad and isn't helpful anymore. Sad to hear that therapy hasn't helped you and it's only gotten worse I share your pain.