Mozilla is a large umbrella foundation that includes the for-profit Mozilla Corporation. The Foundation has always done plenty of work outside of the browser. I do agree that their browser development is having a ton of issues (for example, the lack of development of key features needed for the Android browser to be competitive, like a tablet UI and the slow roll-out of add-ons), but I think those are a result of flawed decision-making in the Corporation which happened independently of anything that the Foundation might be up to.