I don't think anyone is denying the existence of Greybeards, it's more that the field has exploded so much in the meantime that the probability of a random 30 y

I don't think anyone is denying the existence of Greybeards, it's more that the field has exploded so much in the meantime that the probability of a random 30 year old being in it is much higher than the probability of a random 50 year old.