And as for invention of asd etc-
probably exists.
But are you aware of how asd is diagnosed?
I ahve a bad back; never claimed (never knew when bad aged 20 I could, now healed with physio)- a scan diagnosed it.
Ds4 is obviously an ASD case: 2 siblings etc, absences. The process to dx still tkaes years: he will be assessed in every other area first (already now needs glasses, flew through hearing test today, speech delay whcih they are dealing with by sending me on a 2 hour course called child language development: I did developmental psychology as a minor in my degree, and well I mentioned the MA. i will go though like a good girl ). Once he sees the family paed she will use a combination of observations, family history and properly regulated and reviewed tests to assess him: typically our PAed likes to use the 3Di test, but there are some common ones here, a unit based at Cambridge University.
A proper DX is reliable and valid: tehre are I understand some Paeds who don't follow the guidelines but they should be tracked down and dealt with.
DS1's dx took 3 years; ds3's the same despite his severe needs. It was comprehensive.
Now, the mild functional ASD you describe exists but is quite rare: there is a movement called the neurotypical movement which exists to argue that ASD is simply a different personality if you will, and just needs to be accepted, but the rates of depression, eating disorders and unemployment in even the most high functioning individuals with ASD are scary. The neurotypicality movement make a lot of valid points but a key skill lacking in ASD is geberalisation and it's points about them, not the very many otehr people not coping as well.
People with very HF asd simply do not get DLA, heck the new tests wills creen out many severe people. DS3 has severe language delays, an inablity to cope in a room with more than a few people (school has withdrawn him from all integrated teaching), obsessions that rule his life, functional age of maybe 4- but he can ctill at times (if not absent) pick up a pencil when asked which is a fail on ATOS. No chance he could ever be employed or independent in any way: he will end up in a care home. Picking up a pencil when not in absence not being a marketable skill.