@lks Worse. It was entirely due to spite.

A nasty executive George Lucas met with had gloated that by 1978 Star Wars would be yesterday's news because the public was fickle. Lucas was so angry about this that he decided then and there that he would extend the runway of Star Wars' theatrical release as much as possible. He had noted that whenever TV publicity was done - Ford appearing on a chat show, Star Wars characters making a cameo on a variety program - ticket sales bumped up. So he cut a deal for an ill-defined 'holiday' themed special to air in November 1978. This would boost ticket sales and provide a plug for the Kenner Star Wars toy line. But as far as the content went Lucas had a vague notion of a wookiee holiday and the awful idea that the beasts should speak in unsubtitled wookspeak. Then he abandoned it to TV variety writers and a Canadian film student director who had to be fired and replaced by the director of the Elvis Comeback special - but the latter was out of time and could not save it.

Now you know the rest of the story.