Bold statement, there.
To rephrase (and it's really not stated clearly) - you don't think a Linux Vendor has produced a packaged Linux based OS that does not require a "command line".
Wrong.
- Android (Linux)
- Fedora (16, 17, and as far back as 8). Gnome or even XFCE (Linux)
- Mac OS X (BSD)
Now, I am glad that you qualified your statement with "that Windows has a button for". So that's two "Linux OSs", and one "BSD OS" over a bunch of versions.
I'm surprised about Ubuntu (not that I am all that aware of it).
It is clear that you consider command line usage a "flaw".
But, to supply a typical example: someone wanted to know how to change a user's UID and GID (Unix/Linux user id and group id). The answer?
Log in as root, and "vi /etc/passwd". Find and change the line referencing the user. "vi /etc/group" and do the same for the group.
Type "find / -uid 1000 -exec chown 2000:2000 '{}' \+"
to change ownership of the files from user uid 1000 to uid 2000 : gid 2000 (replace the numbers with your desired numbers).
It is fairly obvious that with a small amount of Unix lore, this administration task can be successfully completed. The instructions can be made even more specific, if needed. It is specific to Unix (Linux), and will only ever be needed by someone running NFS in a networked environment (or, possibly, running a license server). In other words, in an office/work environment by an experienced admin, or by a small fraction of home users (a very small fraction).
Is it worth making a button for this? I think the answer is NO. I wouldn't even know where to look for such a thing -- it would take more instructions on how to use it, as compared to "cut and paste into a terminal".
There is common stuff that I would find trivial under Unix (Linux) that I would have no idea how to approach under Windows.
Not CRITICAL stuff; just "nice to have". When I run across one, I just give my head a shake, and ignore it. I expect that you are the same with Linux.
The people who should be or are using Linux know why. I can't advocate change just for change. There must be some benefit.
It may be hardware support. It may be POSIX compliance. It may be performance related. It may be something completely different.
For example -- with 2 and 3TB consumer drives available, I usually recommend a scrubbing, redundant file system. Like ZFS. Of course, that requires Solaris, Linux, BSD or MAC OS X (and it was removed from OS X). Linux has more hardware support, so it would be the choice. At least for the file server. Or, use BSD for a home NAS.
A reason to use Unix!
Talk with the users. Find out what they are after. You can even sell them a service. I wouldn't transition "Joe or Josephine Random" from Microsoft Windows to Unix (Linux, BSD, Apple) without a discussion.