I have one ASD girl, and one NT girl.
I agree it is shocking, it is shocking that I know 3 families who were all told their girls weren't autistic for various reasons, and then a further assessment found they were. My daughter was one. Not autistic because she made eye contact. That was a child psychologist.
It was obvious in the past!!! They were misdiagnosed with childhood psychosis, or childhood schizophrenia and locked in institutions. Or they went to specialist schools, were as now, it is pretty much all mainstream.
My mum used to work in an institution. Many of the ladies she looked after I now recognize as having asd markers. Mostly at the severe end of the scale.
And more children being dx with asd does not take away from anyone else being diagnosed. In actual fact in my experience those with "more obvious" signs are taken more seriously. I cannot tell you how hard I am fighting my daughter's school to recognize her anxiety and struggles because she is "high fucking functioning" and because she masks!! They don't see the struggles I have getting her dressed (severe sensory issues with clothing), to eat, to sleep etc. They just see the little girl getting on with her work, not bothering anyone, therefore she isn't effected by it.
My dd's psychologist has informally dx my dh with asd. He's 50. I can see traits in his dad and his mum. In fact, his mum has quite pronounced sensory issues.