It isn’t like people from different planets visit it regularly; in fact, the only people we see visit that trading outpost regularly are scavengers who (we can conclude from the information presented; well, not quite, but there’s no indication they’re from different planets, so we can still conclude that…) live on Jakku and head there to sell scraps and get resources so they’d live.

And another thing, regarding how it reinforces the notion that Rey is a Mary Sue, in the previous six films the language is implied to be rare.