It was also produced by the television arm of Paramount, with a lesser-known director, and was originally intended to be a telemovie, with potential for an international feature release in cinemas, just like "Duel", "Battlestar Galactica" "Buck Rogers" and "Mission Galactica: The Cylon Attack".
What is this "was originally intended to be a telemovie"? I have never heard or read this before. I'm aware of the theatrically edited versions of the TV episodes of Battlestar Galactica and Buck Rogers that you mention (none of these ever played in U.S. theaters, although I could be wrong about that). However, I don't think TWOK was ever intended for TV first, despite being produced by Paramount's TV arm.
Duel was a TV movie in the U.S. that was successful enough to earn a theatrical release in other markets; IMDB claims a U.S. theatrical release in the 1980s but I'm not sure that's correct, although I did see it in a university film series (on a very weird but interesting double bill - with Patton.)
One aspect of TWOK's earnings not mentioned here yet: In the U.S., it was the first film to be released on home video (VHS) at a popular price, one-half to one-third of the usual price for a feature film; sales were brisk.