I mean it's so logical, I have real troubles figuring out why so many people don't get it.

You can't immediately see what options you have in a command line.

In a UI, you see the "menu" button right there.

If you have no idea about anything, in a UI, you can still click on the menu button, and are presented with more options.

In a command line, if you have absolutely no clue, what do you need to do? Honestly, you have to ask someone who knows (be it a friend, a manual, or web search). You can randomly start typing or press keys, but the chance to get to something useful is very low.

Why do people always assume GNU+Linux relies on a command line these days!? That's like saying Windows does... I.e. it's not true. Maybe if you go back to the Win9x and DOS days.

I swear, if you're going to complain about possibly the only OS that fully respects users and their freedom, how about you actually use it first and understand it's GUI mechanisms before spouting nonsense.

Windows is dominant because of extreme anti-competitive and other nasty practices in the past. The reason it's still dominant is because it has locked itself into it's dominant position since people are used to it (they still do many nasty practices today, as well)