A past discussion of this: http://wikimedia.7.n6.nabble.com/Re-Fwd-Re-Do-WMF-want-enwp-org-td1261498.ht...
Incidentally, there's nothing to say that enwp.org couldn't be made an official service (alongside whatever universal scheme might someday be developed), but nobody seems to have ever gone ahead and done it: https://bugzilla.wikimedia.org/show_bug.cgi?id=30861