Absolutely, I agree of course there is no cut and dry rule and correlation =/= causation etc. I am interested though how children are introduced to food in other countries where, as others have said, the ‘food culture’ is so different. Wondering if all the MNers living overseas on this thread could tell us.
It’s like sleeping - according to most parenting guides, I was making a rod for my own back with my DS by letting him feed to sleep, feed on and off through the night etc well into toddlerhood, whereas DD was in a good sleep routine from fairly young.
Guess who is my good sleeper now 
Similarly my EBF DS is the one who has all the eczema, had issues with glue ear and respiratory issues as a toddler... mix fed DD never had any of those. The only way DS is healthier really is that he virtually never pukes (not that DD does much, but DS always fared better with bugs).
DS is also going to have to be more careful with what he eats I think, DD is naturally skinny. I had undiagnosed GD with him, he was born at nearly 12lb! Perfectly healthy weight now though but he is definitely more ‘dense’ than DD, plus he craves carbs constantly and is fussy so much harder to get veg into him. Both are very active. I do wonder how pregnancy affects them, I had GD this time too but DC3 was a healthy weight as I was diagnosed and kept my blood sugars controlled.
There are so, so many factors that I don’t think will ever be really understood. But anything to improve education, obesogenic culture etc has to be worthwhile if it helps at a population level. It’s too complicated to really know though.