It's odd how many people insist fussy eaters didn't exist in the past, in the face of all the people here who can confirm they did, from personal experience.
I knew a woman who grew up in a rural part of Ireland. If she's still alive, she'll be well over 80 now. She told me once she couldn't eat chicken, never had been able to. As her family were farmers or farmworkers, they probably had chicken more often than equally poor families in towns, and it was probably a treat, but she couldn't swallow it because of something about the texture.
Then there were my two male cousins, one on each side of my family - both now in their 60s, both fussy eaters as kids. I'm not sure how widely they eat in adult life as I don't see them often, but they were brought up on exactly the same sort of food as my brother and I were, their mothers (my aunts) were good plain cooks, as our Mum was, and yet they just wouldn't eat most of what my aunts or my grandmothers or my mother cooked.
And finally, having married a man who by his own account was a very fussy eater in childhood (but with some excuse, his mum was a terrible cook) we had one child on the autistic spectrum who would eat more or less anything and one child who is not ND but who had quite restricted eating in childhood (not now - he'll eat most things and is healthy and active, fortunately).
I am so glad now we didn't make a big deal out of our son's eating. I love food and eating and I hate the idea of mealtimes becoming tense and miserable, instead of a happy time when the family come together and chat. I was worried about my son's lack of variety in what he was eating, but forcing myself to look rationally at what he ate, I could see he was actually getting everything he needed and I could see he was in good health and doing very well at school. So we just worked around it and in the fullness of time he started trying new things and before long he was eating virtually anything. If we'd made his eating into a huge deal I suspect it might have led to further problems down the line, as mentioned by many people on this thread, sadly.
It would have been much harder if he'd been eating a seriously restricted diet with no vegetables, or hardly any protein, or other restrictions that might have affected his health.