I can’t agree with the historian, to think a culture hasn’t realised how to make pointy things and attach them to something else to get them further, seems rather a stretch. An arrow is just a spear with a better throwing mechanism, and combining a tough, angled, probably crafted tip with some kind of long, thin, less worked/valuable item is something that seems fairly fundamental; adding the stick is a step up from a hand-held point and then the common axehead/handle. Even if a civilisation somehow skipped all this, by the time they’re dealing with a modern world, they will have discovered the pointy end goes forward when they’re driving, flying or diving.