Ol' Hootie Johnson, who is now the chairman emeritus of the Masters/Augusta faces this question every year.
And the answer pretty much boils down to: We are Augusta; we are comprised of very wealthy members; we don't need to increase our commercial revenues in exchange for giving up any more control of our tournament. We'll give you what we'll give you.
The beer they serve there is either "Regular" or "Light"....you don't even know if you're getting a Bud, Miller, Busch or Heiniken.
.
Precisely why I refuse to join Augusta. I just can't drink unidentifed beer!!