I'm so sick of this argument about Mozilla. It is like saying a Principal Engineer at Microsoft relies on Microsof because it provides 90% of his income. Last time Mozilla's contract was up for negotiation, they caused bidding war that increased their value over the previous contract...it wasn't Google's generosity. You are a fool if you think Mozilla is beholden to Google.
What if 90% of a politician's campaign funds came from one source? It doesn't have to be overt, I doubt Mozilla makes many decisions by asking themselves, "will this make Google happy or unhappy?" But consider that Mozilla knows what Microsoft and Yahoo's top bids were. Their ability to switch from one funder to another is dependent on how high those bids were.
Yet, I think you'd be right to question the independence of a politician who got 90% of their funding from Google. Maybe it is different because people interested in entering politics have less integrity and produce nothing of value so they are more in thrall to their biggest customer. ;-)
Maybe it is more like the academic projects I've worked on. 100% of the money is from the US Government but none of us are patriotic in the least. We just care about doing the research.
Or how about the US government, which gets most of its funding from US tax payers and China and never seems to do anything that pleases either group.
Or children that get all of their basic needs met by their parents and still grow up to rebel and hate them.
I think politicians are just a special case in being particularly worse than the average human being in terms of ethics, morality and intelligence. :-)