What are you on about? It's simple enough if you've got a full 733 of 148 passengers but all have paid the base fare say £10pp you're not going to make profit, whereas if you're filling your planes full of late booking passengers at £50 a pop you're laughing. Rumour was bmibaby was consistently filling planes full of £10 passengers. Another rumour is they wanted a better deal with the airport than they already had, and the airport refused because they were already getting minimal profit as it was.
The truth is we'll never know