Simon, you have a good point, but while I am not ashamed to admit that I fall on your "rating by others" end of the scale -- happy Debian users make me happy -- much of your analysis seems a bit simplistic and not mindful of the fact that scales include points in between.
If Ubuntu only enticed all of our desktop users away, I wouldn't feel very threatened by it. I'd feel disappointed that we lost those users, but I'd see all the other users we have in other areas, and I could be satisfied with that. After all, Windows still has the lion's share of the desktop users, and I don't feel threatened by it. Or by OS X.
However, when significant development momentum shifts to Ubuntu, when there are lots of things happening there, I do begin to feel very threatened by it. I begin looking to see if development that's happening on Ubuntu is being contributed back to Debian. I conclude that it's largely a one-way street; any improvement I work on in Debian will get into Ubuntu with nearly 100% probability, but any improvement Ubuntu makes will only get into Debian if someone goes out, reads through a patch, and finds it.
See, I'm also motivated by Debian being suitable for many different purposes -- I fall on the other end of your scale too. And I know that I don't want to be today using the software and hardware I was using 5 years ago. And 5 years from now, I won't want to be using the software and hardware I'm using today. My needs will change, things will evolve, and lots of development will be needed for Debian to still be relevant, to still be suitable for all its many purposes.
And if much of the development momentum shifts to Ubuntu, and if there is not even a culture of pushing improvements back into Debian, there's a very real possibility that that won't happen. And then those of us all along this interesting Scale of Superiority you describe will have to decide between giving up and going to Ubuntu, or taking up ballroom dancing.
I've personally decided that if this happens, I won't be taking the former option; Debian is the last linux distribution I intend to work on.