Of course Desktop environments matter, that's why there are so many of them. I would be able to use Ubuntu almost like my own machine if I would install my wind

Of course Desktop environments matter, that's why there are so many of them. I would be able to use Ubuntu almost like my own machine if I would install my window manger and utilities on it. What I meant however is that the defaults of a normal user friendly distro are good enough for those users. There is no need for them to tweak stuff because their LibreOffice and Chrome/Firefox just work with those defaults. The choices are only there if you look for them and at that point you are not a normal user any more.