I think an issue is that people tend to think of Linux as meaning "all distributions." So if something is compatible with X distro version yy.zz, the general idea is "it's compatible with Linux." This, in my experience, is one of the things that leads to mandatory command-line usage --- it definitely is possible to get it to work under a different flavor of Linux, but it's not necessarily easy if you're uncomfortable with a command line.
Another is drivers --- if it's mainlined, it will Just Work, but if it's not...well, it may work, but you might have to jump through hoops and get busy with the command line.
In short: if you view your distro the same way you view a particular Windows release, then I really don't think you need the command line for desktop Linux. But you need to accept that some software isn't "compatible," in the above, user-friendly sense of the word.
I think an issue is that people tend to think of Linux as meaning "all distributions." So if something is compatible with X distro version yy.zz, the general idea is "it's compatible with Linux." This, in my experience, is one of the things that leads to mandatory command-line usage --- it definitely is possible to get it to work under a different flavor of Linux, but it's not necessarily easy if you're uncomfortable with a command line.
Another is drivers --- if it's mainlined, it will Just Work, but if it's not...well, it may work, but you might have to jump through hoops and get busy with the command line.
In short: if you view your distro the same way you view a particular Windows release, then I really don't think you need the command line for desktop Linux. But you need to accept that some software isn't "compatible," in the above, user-friendly sense of the word.