I hear what you are saying, and it makes a certain amount of sense for projects that survive on donations (possibly hard to implement due to the fungible nature of $$, but whatever)
However, Mozilla's revenue is mostly from search engine deals, no? If it is true that the Mozilla foundation is under control of people with goals not aligned with the mission to drive forward open internet, I am not sure what can be done? (Not saying this is true, but there have been a lot of grumbling about it)
Perhaps Mozilla's lasting contribution to the world will be as an apocryphal story, warning others of the dangers of ignoring/neglecting core competencies.
Maybe it's time to ditch the traditional donations system to a per-feature donation. You could even make a policy that, say, 10% of the money of every donation goes to the foundation to use as they please, but the other 90% goes to the development of the specific product/feature.
We need to fins other governance+funding ways for our IT non-profits, or we will keep having this same problem.