"FUEL - are the airlines carrying too little fuel margins to save costs?"
You act surprized.
Read a bit more history of commerce. Maybe the shipping industry which was the fastest transport before aircraft came along.
As far back as camels and horses, the heads of transport have always scrimpted every possible penny in the costs and forced the actual transporters to carry the stress and dangers, while they sat comfy in their tents or mansions, while sipping the finest wines and eating the finest foods they could afford off the backs of the actual transporters.
They'd rather have a ship lost and get the insurance claim rather than give the captain leeway to operate according to the conditions as they occurred.