Nope. It's because, as an example, 200 people want the file you're after, but only 1 person is providing it. Maybe that person is already uploading files and has no slots available. Maybe they're not even connected at the moment.

Now, if the 57 people that have already downloaded it from that person would share, are online, and have an open slot - and both sides aren't firewalled, then people wouldn't be waiting so long.