"prophecy" in the new testament (and I would also argue in the old testament) is a spiritual gift allowing the person to reveal what is hidden. In the Old Testament, it was only associated to making predictions because prophets were to be tested to see if their predictions came true, so predictions were made in order to certify the message of the prophet, but the point of prophecy was never about making predictions.
To see this, consider Jesus and the Samaritan woman, in John 4:17-30:
The woman answered and said, I have no husband. Jesus said unto her,
Thou hast well said, I have no husband: For thou hast had five
husbands; and he whom thou now hast is not thy husband: in that saidst
The woman saith unto him, Sir, I perceive that thou art a
prophet [..] Come, see a man, which told me all things that ever I did
In other words, Jesus didn't predict anything, but he saw what was hidden, and the woman called him a prophet. This is especially significant because the Samaritans differed from the jews by believing that only someone as good or greater than Moses can be another prophet - which is why they rejected all the nevim texts in the MT as they did not consider any of those true prophets.
As another example, we can turn directly to Paul:
1 Cor 14:23-25
If therefore the whole church be come together into one place, and all
speak with tongues, and there come in those that are unlearned, or
unbelievers, will they not say that ye are mad?
But if all prophesy,
and there come in one that believeth not, or one unlearned, he is
convinced of all, he is judged of all: And thus are the secrets of
his heart made manifest; and so falling down on his face he will
worship God, and report that God is in you of a truth.
This is exactly what happened with the woman at the well -- the secrets of the unbeliever's heart are made manifest as a result of prophecy.
Therefore this is what Paul means by the "gift of prophecy" - the revelation of things hidden. And so it's clear why these will pass away, as when all hidden things are revealed, then there is no more prophecy.