>>notpus+YN
That wouldn't make any sense from them. What good would donations for Firefox be if they can't pay the cleaning staff of their office or it's rent or the HR and accounting and legal people that keep the "Firefox core-ish team, and maybe also MDN" employed and running? Even the CEO, even if ridiculously overpaid (one can make an argument that to get a quality CEO in the US you need to pay them a lot, which I don't buy, surely there are people capable of being CEOs out there that aren't greedy as fuck and would be willing to accept a low salary of a 1-2 million $ per year) is necessary for the company, and a bad CEO can ruin them (see: GE, Enron, Boeing, Twitter, etc.).
For a "fun" example of how strict budget destination restrictions fail, take a look at Atlanta's MARTA, that used to have a fixed 50/50 budget split between OPEX and CAPEX by it's funding law, and therefore had brand new trains but everything else falling apart.