But now go and watch a new Linux user try to install the nVidia drivers.
sudo stop kdm
chmod +x NVidia-Driver-Blaa-Blaa.bin
follow prompts. Expect users to know whether to update xorg.conf or not.
hopefully the kernel module compiled correctly
sudo start kdm
Cross fingers and see whether we get a login screen or some breakage.
For anyone capable of being comfortable with that, well good for them.
For a Windows user, they see that as crazyness. Watch a Windows user install nVidia drivers on Windows.
Navigate to nVidia.com and download driver.
Double click, next, next, next. With Windows 7 you don't even need to reboot anymore. And hey presto, it just works.
I would argue that the Ubuntu method is superior to both the above cases for the vast majority.
The command line installation of drivers however is nothing like that.
If you want to know why most users select Ubuntu, look at usability.
Again, if you're completely comfortable with a command line, building packages, know how the different packages inter-operate in the Linux eco system, and can select compatible versions of each, not only are you a candidate to develop you're own distro, you're also in a position most users aren't, and most importantly, shouldn't be just so that they can view a move, a web page, type a document, edit a video file, etc, etc.