No one is saying that Joel 2:28-32 is completely fulfilled. But, it began being fulfilled on the day of Pentecost, according to Peter. And it involves the fact that everyone who calls on the name of the Lord is saved. That obviously is still happening.
So, do you agree that the finality of the fulfillment is at the coming of Christ per this?...
8 Charity never faileth: but whether there be prophecies, they shall fail; whether there be tongues, they shall cease; whether there be knowledge, it shall vanish away.
9 For we know in part, and we prophesy in part.
10 But when that which is perfect is come, then that which is in part shall be done away.
11 When I was a child, I spake as a child, I understood as a child, I thought as a child: but when I became a man, I put away childish things.
12 For now we see through a glass, darkly; but then face to face: now I know in part; but then shall I know even as also I am known.