NPCs exist for to perform a single function within a game. The shopkeeper is there to sell you stuff. The blacksmith is there to shoe your horses. The barkeep is there to give you rumours about that dungeon a day's ride away.
Once you've taken advantage of the function that an NPC provides, it's safe to forget about them. They're not going to be important in the rest of the adventure.
Watto: Well, you won our bet. Shmi has her freedom.
Watto: But if you think I'm going to release Anakin as well...
Watto: Anakin. Her son.
Qui-Gon: The kid? Why would we want him?
Watto: So... I can keep him?
Qui-Gon: Sure. We're not doing any more racing.
Qui-Gon: And you'll need him to take over running Shmi's Mob faction.