Lore question, why are there Hyperlanes? How were they created

I am aware that there will never exactly be any true or canonical answer to this question. I am more just looking for interesting answers, why can't empires ever make new hyperlanes in the lore? Where did they come from?

I ask because I am running a tabletop RPG using Stars Without Number and while it is convenient for doing a point crawl in the stars. I wanted a lore explanation that is interesting. I reason that they might be made with some sort of hyperlane drill that someone created in antiquity but that the drill can only ever create them by traveling between stars in real space, limited by light speed and relativity, so building a new hyperlane would take many many decades or even a whole century, much like a megastructure except there is just no way to rush it