In that discussion, this question was asked:
Why there isn't a President of [WSFS], a Vice President, a Secretary or Treasurer for the Society?My response was that such positions weren't necessary and wouldn't have anything to do. Cheryl pointed out that this is only if you were stupid when you added the jobs. That's true; if we created the positions, we would feel a need to give them some jobs to do. We could, for instance, make them responsible for making sure Worldcons happen and giving Worldcon committees orders.
Which those committees would probably refuse to follow. Worldcon committees are individually much like members of the United Nations, sovereign within their own borders. A Worldcon committee can to a great extent tell WSFS, to the extent that WSFS exists, to go climb a tree with no repercussions other than the potential for their individual convention members complaining about it.
We're a volunteer organization. We can't compel people to do anything. (And if you say, "You could sue them," then you just lost the game, and thank you for playing. Lawsuits are among your last resorts, not your first.) As Cheryl noted, local conrunning groups are, on the whole, run by local fans who have some respect and prestige and are worked by people who respect the individuals and organizations involved sufficiently to take instructions from them. That's fine within a local context. But what happens when a group of primarily American, Canadian, and British conrunners tells an Australian Worldcon how to run their convention? I can imagine it, but I won't print it here. And how could this hypothetical WSFS Inc. enforce their edict?
While there might be advantages of a centralized, permanent, incorporated WSFS, the primary reason it doesn't happen is political, in that fans are fractious and independent-minded and don't like other people telling them what to do. It's something of a wonder we get as much accomplished as we do now.