I think the deal Mr Allardyce attempted to make for £400,000 was less about the money, and more about self-affirmation.
Football is riven with paranoia and back-stabbing, and the further up the ladder you progress, the worse it becomes.
You need to be a very special temperament to be able to withstand the pressures of that job, and even the strongest characters, and Mr Allardyce is clearly one of those, still needs that affirmation deep down that he is wanted, needed, and good enough, and that affirmation comes with the sort of deal he was making.
That does not for one moment excuse his avarice and gross stupidity, but it does go some way towards explaining it.
The corruption that is rife in football from the bottom to the top will never disappear as long as it is run by people who are riven by personal greed and utter lack of responsibility - and that applies to the FA as much as its succession of unsuitable managers.