Why releases are important
Aigars Mahinovs recently wrote in passing in a blog entry:
So, from this perspective, there is nothing bad in money being paid to do this mundane and hard work, if we really, really need to release in a specific time frame (IMHO the only reason to release Debian in 2006, as opposed to 2008, is the Lars tattoo bet).
This is the kind of thing that makes me reach for my editor and flail at the keyboard. There's a really good reason to release: it lets people use your distribution. (Or, in general, your software.)
Releases are important because they give a stable base for people to build their systems on top of. By stable I don't mean 'doesn't crash'; I mean 'doesn't change in a way that affects them'. This is especially important today, when many things that people want to run aren't just compiled and left alone but are built on top of other programs, ranging from Perl to Apache to database servers, that come from you. If the base of such a stack changes, everyone has an earthquake.
Updating an existing system isn't the only source of earthquakes; another is trying to build a second system to duplicate an existing one. There are ways around this, but they make you increasingly cut off from the actual distribution you are theoretically based on (and require you to do more and more work yourself).
(Or as the quote goes, 'you cannot step twice into the same river'. The more you need to, the more you have to build a dam.)
You might think that building duplicates of existing systems is an uncommon thing. But it's not; it happens every time someone says 'yeah, run <X>, my installation works great'. (Sure, they might get the same thing today. How about in three weeks, when they get around to trying <X> on their machine?)
(Old releases have their own problems, so I am not addressing that here.)