Lucas then just compounded the error.
It's very simple: they ****ed up. He couldn't think of some space-age or nerdy replacement for hours/days and decided to go with something cool and settled on parsecs because, well, it sounded cool.
You and he and Kevin J Whatever can argue and debate it all they want: it comes down to three words: it is bollocks. Don't insult my intelligence, Georgey, by making up stories to cover your lack of research/knowledge.
(And just like that, the Covid-19 thread warps into a Star Wars one!)
