It's obvious once you start reading literature and exploring both conditions deeper. The amount is overlaps is staggering.

Both autism and ADHD are evolving as diagnosable conditions. In DSM4 both conditions could not coexist and autism was boys and trains thing. DSM5 made autism possible for women and deer facto created AuDHD. I can totally see some kind of DSM7 where both are seen as outdated and replaced by a new condition like "regulation disorder" or something.