Because the decision was explicitly made when the Fedora project
started
to do releases at regular intervals rather than based on feature-driven
milestones. This is the model Gnome has used with a good bit of success.
It avoids the Debian "work on it for three years until it's perfect"
syndrome, because as this thread is already showing, everyone wants "just
a little bit longer" to get their pet feature just right.
You'll note I didn't say drag it on ad infinitum, nor did I say we
should make it stay that length of time permanently. I said for the next
release make it a specifically longer length of time to do development
work in.
That's all. I'm saying that I think there is room to discuss a different
timeline other than the 'every 6 months, release' timeline and I think
that given the tasks set ahead for FC5 that I've heard batted around
over the last N months that it would be worthwhile to lengthen the time
for development for this release.
-sv