Are prophecies something that destroy history?
Doesn't knowing that something was predestined from the beginning of the work make everything that was done before in vain?
It takes away all the weight of the decisions, and renders useless everything that the character has worked hard to build. Because logically, no matter what he did, it would all end up the same.
Depends on the prophecy to a degree. Prophecies are often vague, and the exact meaning is often unclear until it has been fulfilled.
But also, it's not like knowing that 'the good guys win' ruins the story. That's almost every story, everyone is expecting that from the beginning. What matters is how the characters get there, the struggles they overcome, how they change and grow and come into conflict with each other and how that shapes them and who they are and their path. A story is about the journey, not the destination. You could compare it also, to life itself. Life is about the journey, not the destination. The destination is immutable. Death. And then being forgotten. It WILL happen, it's only a matter of time. That doesn't stop people from caring about what happens before that.
Plus, prophecies (except for a certain subset, the kind enforced by the abstract, god-like entity/force of 'fate' or 'destiny') don't force things to go a certain way, they don't write fate or make anyone do anything. They are predictions, it's knowledge of what will happen, but what actually makes that stuff happen isn't the prophecy, it's the characters (sometimes the prophecy is responsible for pointing the characters in the right direction, self-fulfilling prophecies, but it's still the choices and effort and power of the characters that make it happen). If the characters didn't fight and give their all, they would fail.
The caveat being, if that is the case, the prophecy wouldn't have been made in the first place. So really, a prophecy is more a guarantee that these people will put in the effort even with the seemingly guaranteed nature of the future, and that the effort of these people will be rewarded- unless it's a fallible prophecy, where the future-sight is limited somehow, like only showing a likely future, or is more of a guide to a desired future than a prediction, or where the prophecy would have come true, but by gaining knowledge of the future, the future changed, resulting in, essentially, a self-defeating prophecy.
Of course, when prophecies are handled unskillfully by the author, it can seem like the only reason things are happening is because fate and coincidence is bending over backwards to make it happen, because, "The prophecy!", even if the prophecy isn't justified as the kind where fate/destiny itself is backing it up to make it happen (or even if it is justified that way, but still handled poorly) and at that point it devolves into an obnoxious form of plot armor. However, a fate-type prophecy, handled well, can be really interesting.
Prophecies have interesting effects on characters, where they struggle with the implications of being a prophesied something, and either struggle against destiny or feel like they can't, or they get warped by feeling like no matter what happens victory is assured because of the prophecy, and all of that can be really interesting from a reader's perspective. Times where the characters in-universe make false assumptions about the nature of the prophecy, (fate vs prediction), and struggle with that, possibly making mistakes based on that false assumption- all delicious story material.
So actually, I've changed my answer. "Not in the slightest". Or rather, no more than any other trope or literary device can cause damage to a story's effectiveness when handled incompetently.