User blog comment:DaNASCAT/Technical Update: March 7, 2016/@comment-5558012-20160307231322/@comment-5558012-20160309153645

Of course this would still have been a problem, and, dependent on the wiki, no they can't promote themselves. Bureaucrats are not all lone wolves and don't all get to be the only decider on user rights. If they aren't Admins, they don't get to promote themselves to such. This is a community and policy decision.