Seeds fall off quickly on public trackers and the people who do long-term seeding on publics tend to end up seeding larger libraries. So you'll often be the one person in the world seeding a large number of torrents. Multiple leeches is only a theoretical help because when it finally seeds out, half the people quit immediately, some hang around to seed to the last leechers, and a couple hang around for a week or two before feeling they've done their due diligence and signing off. Things are quiet on that torrent for a month or so, and then a new leech shows up and the whole thing repeats again. It's why I stopped seeding on publics: it's extremely demoralizing to finally get copies of something out to the dozen or so people who have accumulated, only for every one of them to fuck off right after they finish.