"Where did all the good sharers go? Like Zandman, Dragonite, Odds&Ends or Justdoit? Going back further, sharers like Wintermute, RacerX and Weener?"
Most of them I'd agree. But as far as "Z-man" and "justdoit", I totally disagree. In "Z's" case, it was quantity over quality. Sure, he'd post tons of links, but many of his sets were incomplete, or re-sized/re-compressed. Tell him that he's not sharing originals, he'd go ballistic on you. Justdoit just shared what he liked, i.e. bikini sets only. Ask him for the complete series, he'd tell you to pi$$ off.
The rest of your list, yeah, agree. Good posters. There was a Ceandydoll poster who didn't advertise himself, but would only share original material - at a time when it was hard to get their stuff.