> If I understand correctly, you say that software as an art form must by default have a conventional and easily usable UI or means of interaction, ("practical considerations of the medium") before considering anything artistic such as the gameplay itself?

Yes. Exactly!

And in many cases (especially with games), people DO play around with the practical necessities and often stumble on something inspired. Like HomeStarRunner's "Virus" SBemail, or fourth-wall-breaking adventure games that comment on their own interface. But I think in DF's case it falls flat.

Western music is written in a consistent scale for practical considerations: it was discovered that writing music in a mathematically consistent format made it easiest for musicians to play and reinterpret. Sure, people deviate, but the vast majority of those efforts are terrible. Cinema -- even avant garde -- is constrained to the limits of film, audience attention, and patterns in storytelling, and the viewer generally expects certain things. Literature is constrained by the practical considerations of books and the written word, and so written text is formatted consistently per reader expectations. How is software any different?

Or the thought-games played by the Espers in The Demolished Man.

Personally I don't think the UI was planned out that much; maybe "it gradually got so" as the song says.

I think it's a bit like the qwerty keyboard. Maybe there was a rational for it at one point, but now it's just a thing you memorize and then don't think about much. In DF the 'loo(k)', '(v)iew', and '(q)uery' commands do similar but disjoint things which could easily be combined if Tarn really wanted to stop working on features for a while. Since he doesn't, it's just a thing that you memorize and then no longer need to think about; it becomes very much like touch typing.