Monopoly and oligopoly are very similar. A conspiracy to raise...

Monopoly and oligopoly are very similar. A conspiracy to raise prices against the consumer, credit cards to actually fit in the same vein their fees are outrageous and there is no choice but to use them.
It's not possible for me to set up a credit card company in competition so they behave in monopolistic behaviour.
There are of course degrees of monopolistic behaviour - nothing is black and white.
Most proffessions are also monopolies against the consumer, we pay so much for legal services as there is so much training - is it all strictly neccessary? All the vested interests will tell you yes of course.
Same with regulations on cabbies, existing to keep prices up.
The value judgements are I think not helpful to a discussion of the facts:
Does Uber have a lower cost model?
I think the answer is yes and in this case it's my preference to invest in the lowest cost producer with the best competitive position.
I am not super comfortable with buying a higher cost company like cabcharge - the shareprice has fallen a lot but I am not sure it is cheap.