ThanksI just looked up gigantea 'alba' and out of the several dozen awards to date for Phalaenopsis gigantea, only 1, is to the alba form! And it was just a JC, "Judges Commendation" for the alba color form. It only had on inflorescence with 5 flowers. 2 images were in the AOS records for that plant, and Yes, it was not a miniature plant.
That causes me to think that they might be difficult to grow and to flower. The JC does mention "cupped" flowers. Or maybe there are not many plants around. A third possibility is that no one grows it well enough so that it could earn either a flower quality or culture ward.