I moderated a list for parents of gifted kids at one time. Bright kids tend to have bright parents, so most of these people were used to being the smartest person in the room and most of them defaulted to assuming that if you disagreed with them, you were basically "just stupid."
It was really challenging at first to get people to assume the other person was also smart and likely had good reasons for having drawn different conclusions.
I think we can at least confidently say that other people are more willing to listen to an NP winner. That could completely explain the phenomenon.
Later in life the people responsible for their success have moved on to their own careers, and the celebrity genius now has to start over without the chemistry or medicine equivalent of The Wrecking Crew to keep them on track.
Nobel prizes aren't given for being the best scientist, they're given for novel discoveries. And to make a novel discovery often means you're putting forth a theory that's probably a bit "out there" to begin with. Couple that with the fact that once you've won the Nobel prize you can convince yourself that your shit don't stink, so that when you make further wildly outlandish claims you can just convince yourself the masses just don't "get it" like how they didn't necessarily get it before you won your Nobel.
Musk is my current favorite example of this. I think he was undeniably a visionary when it came to electric cars and private space travel, but his success in those areas (in which he was heavily guided by his underlings, similar to what you point out) convinced him he can be an "unrestrained genius" in other areas, when in reality he's just a douche bag.
I dislike Elon Musk generally but you have to give credit where it is due.
I am failing to find the accounting of how he reportedly deduced the chemical nature of sickle cell anemia, but it is something else.
That he chased vitamin C does not make me think any less of him. Plenty of science is wrong and goes nowhere after significant effort.