In the case of Symbian hundreds of millions of people all around the world bought Symbian devices right up until the point it was deprecated. It certainly didn't fail the 'end user test'.

With regards to Linux did you see this piece by ZDNet Australia? Just before the release of Windows 7 they took out a laptop loaded with KDE4 and showed it to random members of the public telling them they were looking at Windows 7. Notice how they ooh and aah and say 'Wow, that's amazing!'?

The thing that really sucks about Linux is that most people don't know that Linux doesn't suck. In fact many don't even know what Linux is. They buy a PC and it comes preloaded with Windows, that's the way it is. My sister-in-law wouldn't even believe me that you could run a PC without Windows, she thought I was talking b0ll0cks when I said my laptop didn't have Windows on it.