Revelation, if there is such a thing, didn't end with the last conversation an angel had with a human being.
Every day, scientists learn just a tad more about their specialties, and with that additional knowledge we understand a little more about the universe in which we live, and that understanding is part of the on-going "revelation."
Reason demands that revelation is on-going.
Respect for the universe demands that revelation is on-going.
The continuing existence of humanity demands that revelation is on-going.