So, there’s a significant gender difference here, possibly with diagnosis but likely a deeper connection. Alternatively, it might impact both but this study didn’t have enough statistical power to notice the correlation.
Same happens with ADD. A lot of parents are diagnosed in hindsight when their child is diagnosed. “Wait my son had ADHD because he acts like this? I acted exactly like this.”
But I also have known women who will happily bounce from topic to topic and the hint of a tangent, and it’s obvious to me they should have been diagnosed by ten. Some have been as young adults, some older, one at least I don’t think ever was. It’s not just different presentations. We don’t want to see it.
Inattentive is a bit of a misnomer, too—it's not that they can't hold attention on something, it's that they have a hard time controlling where their attention goes. This is another reason why this presentation often flies under the radar: "my {daughter/son} can't have ADHD, {she/he} can stay focused on {favorite activity here} for hours!"
At the same time the term has been more widely applied over time to include people with minimal intellectual or linguistic impairment, but that doesn’t mean people with such profound issues no longer exist.
Thus, if you’re talking about the full autistic population overall they are going to on average be worse at basically any task.