The memberships needed only to be "elite" (self-confident?!?) enough to be able to say to the USGA and the PGA Tour, and most of all themselves; "We don't need to host a major championship to validate our course."
(The interesting thing, thereafter, is what do we say about the Open rota: Muirfield, TOC, Carnoustie, Troon, Turnberry, Lytham, Sandwich, Hoylake, etc.?)