You have an excellent point there. A recent example is that it took FREAKING forever before Firefox 3.5 was in the Ubuntu repositories, and it's still only in Jaunty. If you're running an older version (like Intrepid or Hardy) then there is no simple way to run 3.5. Seriously???? I need to upgrade my entire OS to upgrade my browser? WTF!
You can of course install from source.. That's easy enough for most of us here on HN, but not exactly end user friendly.
IMHO part of the reason package repositories for Linux distro's don't work as well as something like the iPhone App Store or the Android Market is that they're to fragmented. Even for a major open source project like Mozilla, getting your latest release into every major version of every major distro's repositories is a pretty major undertaking. Not to mention of course that the iPhone App Store and the Android market allow for both open source and commercial software.
I know. I tend to exaggerate a little from time to time (and that not everyone likes it), but I always try to make it engaging or, at least, entertaining. When I saw two different important software vendors embracing the idea of software package repositories, it came to me the idea is taking hold. My iPod self-updates apps installed in it. It is not as sophisticated as APT or YUM, but it's an idea whose time has come.
When what you want isn't in a repository or you want a newer version than the repository has is where you hit problems. The Mac and Windows tend to get around this problem by having a decently stable set of libraries that programs work with. With Linux, because everyone is free to have or not have anything, programs can't count on what may or may not be installed or what version it might be. And if one were to upgrade one library, it might cause incompatibilities with certain programs and if one were to install a newer version of a program it might depend on that newer version of that library. Many Linux distros get around this by not upgrading packages in repositories beyond critical fixes for a released version. And that does bug a lot of people. It's one of the reasons new Linux distros are released so frequently - an upgrade of the OS is also an upgrade of the programs you're running on it.
And part of this is that Linux is progressing rapidly. We don't want a stable set of stuff because we couldn't improve as quickly that way.
But it's a little bit brusk to say that Linux is just superior because it has centralized application management. It's both a positive and a negative. And, to an extent, it's a solution to a problem that the Mac and Windows don't have - that programs can't count on what's going to be on a given system or what version.
It's cool. It makes some things easy and nice. It isn't some magically amazing thing that always works in your favor.