Science has improved, yes. We've discovered there are many people who are able to produce a set of coping strategies that effectively mask their autism.
This is what science does -- we continuously challenge what we know and change our definitions when we learn. The people who are experiencing diagnosis with autism and ADHD today will seem totally different than the diagnoses 50 years from now.
You cannot hold on to one, old definition for something like autism (or any other non-neurotypical behavior) and expect it to remain the definition, unchanging.
This is what science does -- we continuously challenge what we know and change our definitions when we learn. The people who are experiencing diagnosis with autism and ADHD today will seem totally different than the diagnoses 50 years from now.
You cannot hold on to one, old definition for something like autism (or any other non-neurotypical behavior) and expect it to remain the definition, unchanging.