I will give you a big technical reason why they want its predominance as the staple mount to not increase over the years.
Not because they want to keep it prestigious. Not to placate people that have it. Not to keep the model rare. Nor for any justification that they want to shuttle the gold sink to more current content. The key reason is to cut down on AH api calls. If everyone and their grandma is using the AH in all locations outside what they have planned. It will bog down server stability than is already whimsical as it is now.