If you believe that Mozilla should fundamentally be Firefox (and I am sure many would agree) you will probably be frustrated to learn that Google gives Mozilla about $500 million a year for that and that The Core Firefox team is about 40 people.

All the rest of the formerly 1000 employees do other things on behalf of Mozilla but generate basically no revenue.

I personally place a huge value on some of these "other" projects though such as MDN the absolute best documentation out there for the web.