A pure CLI is an arbitrary constraint on program design. CLIs and GUIs are not adversaries or mutually exclusive.

I see no evidence that designers are opposed to command interfaces given that many of the graphical programs I use incorporate them where appropriate.

The world isn't black and white. GUIs can be fast and pointing can be faster than typing. In other cases, a written command is fastest way to get exactly what you want.

Do you measure how far people get in the video? People might click to hear Spolsky, but not for the whole hour.

My understanding: we measure it (Michael Pryor posted a link below), at least some people really do stay glued to the tube for a long time, and then they convert like crazy.

Here's a link to Michael's post: http://news.ycombinator.com/item?id=2588718