They get a C.
Ever since I was in my teens I have always said i pretty much raised myself.
We get along fine now (I am 50s, they are 80s) and i have somewhat forgiven them since they were a product of their time (the Great Depression and WW2), and of inattentive parents themselves. However, they would never acknowledge their bad parenting even when i spelled it out for them, and they called me spoiled. This, after not seeing them from age 17-23 and putting myself through college and grad school thousands of miles from "home."
I was/am a completely different parent to my 19-year old daughter. She knows my feelings about her grandma and pop-pop and we discuss everything. I showed her this thread and she gives me an A
Interestingly, my parents are loving, attentive grandparents to my daughter. Maybe people do change.