Aside from the "gen-u-wine™" thing I actually want to have the global-inbox enabled in Area 51 (maybe http://stackexchange.com too).
We finally just added the gen-u-wine™ StackExchange™ MultiCollider SuperDropdown™ to Area 51! Sorry that took so long.
As to the why, Area 51 does not have an API. While this does not mean they couldn't show the data from the other sites that do have an API, I suspect it is omitted to try and avoid confusion.
I think they have not yet figure out how to integrate the two different types of sites they have created. Area 51 draws on the other accounts differently than a usual stack exchange account. Maybe they just haven't got a coder to the problem, or they are waiting for more data on the issue.