It's a long old haul getting through Definition and Commitment. When the magic 100% commitment is reached, it's a big moment for those who've contributed.
So why the wait for the site? Seems to me the typical wait is several days. How much "preparing" is required, behind the scenes, for a private beta? Surely you flick a switch?
BTW one of the sites currently in 100% limbo is http://area51.stackexchange.com/proposals/1369/gardening-and-landscaping.
OK, so gardeners are supposed to be a patient lot, but stilll.