How?
Did you read verse 16? Peter says what is happening in Acts 2 is that which he quotes in verse 17. So it doesn't mean this is going on every day for thousands of years afterwards.
But you should look at Revelation 11:3
John tells us two witnesseses will come, and guess what they will do?
Prophesy.
Revelation 11:3
And I will appoint my two witnesses, and they will prophesy for 1,260 days, clothed in sackcloth.
So, there is prophecy that obviously comes AFTER the Revelation of Jesus Christ was written.