I think my mom enjoyed having someone to share the struggle with, but she wasn't interested in being a motherly figure. I remember my mom was bored to tears during school functions and she had no love for other children in general. My father was just a self absorbed prick. My mom is completely elated to be a grandmother though, similar to your parents it sounds like.

The conclusion I've come to is, I doubt similar people would get married now let alone have kids in today's environment. From my perspective I do harbor some hard feelings toward my mom and dad for being kind of shitty (in different ways, respectively) - but I also realize a lot of it was born out of true generational ignorance.