They laid off 320 people that year. If she had taken a salary of $0 they could have paid them each <$10k with that salary.
I don't think the salary was appropriate, but like a lot of these CEO compensation things, it's not going to make a huge difference to the final problem. Which was people switching to Chrome which google was pushing aggressively everywhere. ... and I guess purists here abandoning them for... Chrome? Again, no idea what the point is here. Mozilla has flaws, so screw 'em?