+1From a practical standpoint it's not a big problem. Firefox is not installed by default in Kubuntu anyway so I already have to apt-get install firefox as one of my first actions on a fresh install.
But I agree with smellyman, Firefox has symbolic value. Mozilla may be sponsored by Google but their intentions and spirit seem totally different. Firefox was likely the first open source application that I used, starting on Windows ~ 10 years ago. When I installed Ubuntu I was glad to see Firefox there installed already I have used it ever since on any OS installation and still do today. According to what I read Firefox is slow compared to Chrome(ium) but I haven't noticed that myself. The extensions were awesome and still are today. Firefox Forever!