It used to be cheap. But prices have increased massively in the last decades. For example, in Stockholm the inflation-adjusted price has increased by over 200% since 2000. The price has increased much more than the price of gas which drivers complain about all the time. Politicians in Stockholm motivate raising prices with "well, it's still cheaper than in other cities so be happy!" But I suspect politicians in other cities use the exact same argument to raise their prices.