That's precisely my point. In the Linux world, your distro version is inextricably linked to the versions of every major and minor software package in a way that just doesn't happen in Windows.
If I stuck with Lucid, I'd still be using Firefox 3.6. (Yes you could add a PPA, but opening the terminal is beyond the technical skill of the average user.) Linux won't succeed on the desktop until the phrases "Upgrade Firefox" and "Potentially bork my entire system with unexpected regressions" don't go hand-in-hand.
FF will still auto-upgrade to 6 even on an XP machine.
Ubuntu has a security policy to upgrade supported versions to the latest supported browser version. So, in Lucid, if 3.6 is still supported by Mozilla, that is the version still on maintained (you know, for consistency...thing thing most people here are railing against).
However, as soon as mozilla drops support for 3.6, the latest supported version is installed. This happened for Lucid, as I understand it.
This is a sane policy, IMO.
If, however, you are on Lucid and want to run a different version of Firefox, it is rather trivial. You can find it in Ubuntu Software Center after adding a repo and install it. This is NOT what most non-technical people want to do, however, and that is why the policy makes sense IMO.
And, I agree, FF auto-upgrading itself to 6 is nice on OSX and XP, but that is a Mozilla thing, not Linux. Mozilla makes that difficult to do and the various linux distros need to deal with it.
> your distro version is inextricably linked to the versions of every major and minor software package in a way that just doesn't happen in Windows.
What's the big deal with versions? It's not like it's too much trouble updating Ubuntu from one version to the next (you know you can turn off Unity). Most of the time, you can even continue working while it upgrades. This is not like Windows where you have to reboot the machine with the install media and wait a couple hours to get the new version.
And while the Firefox teams does an amazing job making FF 6 for XP, the same can't be said about the Internet Explorer team. If you want the latest IE, you need to upgrade Windows.