I don't think that you can learn how to heal unless you've really needed it....I mean its not something that you can learn in advance. So what if your parents did tell you about your past? There's a 99.9% chance that you'd just say "well I'm ok, I don't need to learn coping skills or grounding skills or anything like that". I've known all about my past. I've been in therapy since I was 10. I tried to get help for so many years and it didn't really amount to a pile of beans. The truth is that the squeaky wheel gets the grease. If I was "ok" and just trying to learn how to be healthy-ER then I would have been given some crap advice that's given to people who have problems along the lines of being sad that they have to wake up and go to work on Monday mornings. I wouldn't have been eligible for ANY of the treatment that was the most helpful for me (two stays in the trauma unit for almost two months and two weeks in intensive trauma therapy). I'd still be floundering along with talk therapists who just sit there, nod, and say "how does that make you feel?" How would I know pre-breakdown what types of therapy would help? Most of my therapy came only after lots and lots of research on PTSD.
I understand why you're bitter, but I think the reality of things is that even if you did know, your path in healing wouldn't be any different. I've known other people who have been traumatized and I know that they're one MINOR trigger away from going full blown, but the truth is that they all just turn a blind eye, they choose to not dig into things. Why would you try to fix something that isn't yet broken? (Not that we're broken, but you get my analogy.)
And MANY people have crappy abusive pasts but aren't as affected by it, and don't necessarily develop PTSD, anxiety, depression, etc. I think you're making an assumption that all those who have bad pasts are destined to have mental problems, that by simply knowing about your past you'd somehow be able to know of the crap that awaits you in the future? Some go their whole lives with no breakdown, some break down in their 20's, others in their 30's, and so forth.
Even if you did tons of pre-emptive therapy, you can still be hit with a rock bottom hitting sort of breakdown. The truth is that you don't know what is going to trigger you to go over the edge. When my symptoms were at their worst, there weren't that many skills I really could have known in advance that would have "saved" me. Skills are learned through trial and error, and if you don't try them out and practice them when you're symptomatic, then how do you know they work?