I wonder whether the difference between a black cab driver and a bus driver is partly down to how they earn a living. A bus driver is employed and so doesn’t take the ‘revenue risk’ of a delayed journey. Black cabbies are self employed, so possibly feel that the streets are their workplace and the rest of us are sodding up their day and income. I have no evidence to back this up, but it feels plausible.
That said, it’s no excuse for poor driving.