I know you, perhaps, are not feeling "heard" here, and I can understand that perspective.
However, from our perspective, consider the diagnostic criteria really haven't changed since the mid-90's, but awareness of the condition has. We were always autistic, it's something you're born with. What has changed, and perhaps more to the differences in the experiences you are sensing and trying to sort out, is life experience, as well as, the cultural experiences that have evolved over the years. The parent-child relationship has significantly changed, almost 180* change since the 1980's. I don't want to get into it. You probably don't want to hear it, but for better or worse, it was "wildly different", as you put it. As such, we are the survivors, and I do mean survivors, because the suicide rate was, and remains, disproportionately high. Us old farts, as a group, most certainly have a totally different view on life, having experienced most of our lives as "failed neurotypicals", not as autistics. We were punished, ridiculed, and marginalized for our autistic behaviors, as we were expected to behave "normal". That comes with totally different "baggage".