I will start by saying that I have not used Ubuntu in a while, so things may have changed. Also, while I have worked for Dell, I have mixed feelings about their products (no, I am not a Dell fan boy).
First, when I had a fresh install of Ubuntu on the computer, to get the networking setup, I just had to plug in the network cable. By default, the network card was configured to DHCP. Granted, that won't work for PPPoE connections, but if you have a router that is pre-configured properly, you do not need to worry about PPPoE. Technically, any Windows based computer does this as well, if it was pre-configured properly.
Second, Ubuntu, by default, has all the basic legal applications pre-installed (like word processor, spreadsheet, etc). I say legal, because mp3 and DVD playback requires extra steps due to US laws (although Dell is the only company that I know of that ships Ubuntu with a legal DVD player pre-installed). The question then becomes, does the user KNOW the difference between a brand name and the type of application it is? For example, that MS Word is a word processor, or that Internet Explorer is a web browser and NOT the Internet?
Third, Dell has tried to make using Ubuntu as simple as possible (I was working at Dell when they introduced Ubuntu systems, and I had access to some of the documentation). Dell ships their Ubuntu systems ready to go, no tinkering needed, all drivers pre-loaded, etc (with the above mentioned mp3 playback issue). Or they did while I was there.
Granted, if you just download a Linux ISO file, things are going to be different. And yes, Linux is not for everyone.
I think part of the problems is that Microsoft dumbed down the OS too much, and now computer users expect a lot of hand holding when they use any OS. Then again, that is MY opinion and yours may vary from it.