My son who is high functioning ASD is socially aware and to meet him, you would never guess he has autism. Many people with autism, especially girls, are wonderful at masking their symptoms. A lifetime of trying hard to fit in has taught them this. My daughter is on the spectrum too but she masks so well outside of the home, that nobody would know how much she struggles.
I hope my kids go on to have as normal a life as possible.
Unless you know Neil and Chris on an intimate and personal level, you can't say that they don't have autism. If they say they're both a bit autistic, I take them on their word. We don't know whether they've struggled or ever been diagnosed. There is still a big stigma around autism, can't see them casually associating themselves with it. I'm sure they know what they're talking about.
I've been a social communicator all my life and ran magazines, was out and about representing them and being the face of them, involved on the boards of community organisations - nobody who knows me would think I could be Aspie. But then they don't get to see the whole picture.
You've had plenty of people on this thread with real life experiences of being on the spectrum themselves or having children with it. We are the experts. If we see all the signs in Neil and Chris then the signs are there. We live with it. Since my son's diagnosis I've spent every spare minute researching autism in its many forms. My son's type is pathological demand avoidance which is massively challenging but he can chat away to people normally and is quite social.
Showbiz Neil is likely just a mask. One that took years to perfect. They didn't tour for four years. It was about 15 years into their career that he really became a luvvie. For years he said he preferred early nights at home and said having a number one song felt like "vaguely nothing" and like having a cup of tea.
ASD being a spectrum means different symptoms at different levels all the way across. One child might not be able to talk, but another might be a brilliant communicator who has huge sensory processing difficulties.
And autism is not always devastating. In fact, it can have some up sides. As Gary Numan explains here (and yes, he's diagnosed and has struggled and been thrown out of several schools).
https://youtu.be/aTKHZeP-IZQ