Firstly, let me say that it is extremely admirable, and rare, that you have been able to pursue the cause of the difficulties that plagued you for years and overcome them.
Having said that, and I hope I don't sound insensitive, but that should be enough. Your parents, by your own words, are nice people. Perhaps they did the best the could with what they had. They didn't give you the disability, they had the inability to accept it.
What if, what if, what if.....Life is full of what ifs. Part of being a successful adult in this world is not wondering about the what ifs, but dealing with the what is. You have two choices, continue to hold your resentment (your word) toward your parents which will prevent you from having a full relationship with them, or move forward with "life is what it is" in your heart and be grateful for the success you have today. You may want to move forward by doing some talk therapy with a therapist.
Holding the resentment and blame is like a canker sore - it can fester and grow and take over all the positive you have been able to accomplish. Holding those negative feelings in your heart will make you unhappy in the long run. Finding the forgiveness within is what will enable you to live and love fully in the future. My two cents.
Again, I think you have done a remarkable job of identifying and overcoming your disability.
Sharon