Almost all London taxis are of a single car type, the Hackney carriage. Compared with the taxis of other capitals, for example: Berlin and Paris, do you think that London taxis are monotonous?
It's well regulated due to traffic jams. And we don't need to pay more to ride on a Mercedes Benz like in Berlin. And in Paris, they don't talk in English. Voila.
Nope, that's their thing. There's plenty of private hire firms (and uber until they're kicked out) to choose from if you have some sort of black cab phobia, but you miss out on the "the knowledge," the banter, and the scurrilous gossip.