I shouldn't say none, but I could probably count all of the ones that did get finished on one hand.
And then how many of those are actually good?
The thing is, people get bored with it before they even really get going, abandon the project, and then decide to start a new one, and do the same thing all over again. Take a look in the Projects/Games forum, and see how many people have multiple projects.
Of course, there are members who will finish a project, but most of the time they aren't worth checking out.