I have two nervous cats that had a stressful first year in a shelter - illness, dogs barking, little care. They gave them to me 1/2 off. The male has never purred, and won't sit for long to be pet. The female finally after 2 years old is letting me pet her (she does purr).
I always assumed the lack of purring was due to childhood trauma and nervousness. The male cat is very needy and always needs to be sitting on me or another cat when in bed. He spent his first half year at home always sitting on top of his sister.
But I am surprised to hear there are cats out there that are not physically damaged from laryngitis or emotionally stressed. My cat is still not a very happy cat but he is getting better.