Mozilla's mission is vital and they have been very successful overall. Much of the credit must belong to Mitchell Baker, Brendan Eich, and others who led the organization until now but I'm starting to be concerned about the leadership's future, a future that is important to everyone -- I'd much rather lose almost any software company than lose Mozilla. * Why do they appear to have difficulty finding a long-term CEO?…
I can't speak for the board here, but lack of stock options and the like probably has something to do with it.
I expect that it's also difficult to find a CEO that is willing to operate in the sort of environment described in http://blog.finette.com/on-mozilla (see the quote from John Lilly in there). This extends to broader culture fit issues: finding a CEO who would be a good culture fit for Mozilla's stance on openness and the like may not be simple.