The ancient religion of Persia crosses paths with both Judaism and Christianity, through Cyrus who is considered righteous, and through the magi who came to worship at the birth of the Christ.
For Zoroastrianism to have given way to Christianity or Judaism, with which it had much in common, or to have absorbed elements of these faiths would have been a natural progression. To have been strangled as it was by Islam seems to me one of the great tragedies of the middle east. It turned what was once one of the vibrant civilizations of the world into just another muslim backwater. What good remains in modern Persian culture is not thanks to Islam but in spite of it.