Writing Forum

Honestly, I think it's a remnant from fairytales and, especially, mythological stories which have inspired fantasy and science fiction quite a lot. As I mentioned above, I think it's serves as a mean for foreshadowing but also a way to give the story a 'mythological' feeling and thereby adding depth since most readers will ,at least subconsciously, make the ancient myth-prophecy connection.
Yes, I do think foreshadowing and the depth/mythological feeling can be achieve in other ways, but the prophecy is a short and effective way of achieving this.
I don't think writers should keep away from using prophecies as long as they're aware that it is a somewhat overused trope and using them properly might not be as easy as one might first think.