Additionally, Mozilla is all about making the open web succeed nowadays, and it's focusing on things that make the open web move forward - which I fully support. The largest threats for the all of the open Internet space nowadays are clearly in the area of the web and we need to push forward there to make a difference. We just can't have all data, communications, and other information of people on the Internet be buried in walled gardens without the people themselves having full control over their doing.
And for that, we need to care that Mozilla stays relevant on the Web so we can have an impact there with what we are doing. And keeping Firefox at a high market share, maybe even making it rise, is the way we can make sure that Mozilla and our mission stay relevant.
Sadly, telling the same story with SeaMonkey in there doesn't work. And I even have to agree with people telling me that no matter how much SeaMonkey reflects the Mozilla mission, it's not really advancing it. The SeaMonkey project is fine and nice, but it's not in the main focus of Mozilla, and I fully understand that sentiment - even agree with it to a good amount. And as much as I like the SeaMonkey product, I really want to drive the Mozilla mission forward, and currently I tend to get tied up in administrative work that isn't tightly connected with moving the mission or the open web forward.