As a reader, I'm extremely lazy, and can never think of anything intelligent to say about the story I've just read. As a writer, I'd be happy just to hear that someone read my story even if she didn't like it. Seriously, though, I can see both sides. I think people should send feedback. I don't think people should feel guilted into sending feedback.
Feedback can be a touchy issue and engender a lot of jealousy.
Discussions about whether writers feel that they get enough feedback are often couched in very cautious terms. Writers don't feel comfortable mentioning actual numbers because it seems too much like participating in a popularity contest. The answer to the question of whether writers get enough feedback is always no. Well, that depends. However, comments like 'it would have been better if it had been Mulder and Skinner that Scully walked in on instead of Mulder and that stupid rat bastard Krycek' are not constructive criticism.