While I agree with your last sentence to some extent, I do believe that having a vibrant, viable Mozilla does serve to empower Internet users in a somewhat similar way as the GPL does.
Linux and other GPL software I believe has served as a viable alternative to closed/walled gardens like the Apple ecosystem (and I say that from my Macbook with my iPhone and iPad close at hand). Every time we lament the issues of loss of user power in walled gardens, I think it's substantially true that "it could be even worse" if there were no countervailing forces, like Mozilla.
If your mission statement is too concrete, it can actively prevent you from looking at opportunities.
Mission statements are like a wind in the sails of the corporation. It doesn't replace the role of the rudder (that's the job of the C level leaders), but it does lead you in a particular direction.
Linux and other GPL software I believe has served as a viable alternative to closed/walled gardens like the Apple ecosystem (and I say that from my Macbook with my iPhone and iPad close at hand). Every time we lament the issues of loss of user power in walled gardens, I think it's substantially true that "it could be even worse" if there were no countervailing forces, like Mozilla.