Price controls is an unfairly simple way to say that the company signed a long-term contract in which the city covered 2/3rds of the construction costs and set the fare at a maximum of 5 cents for most rides for the next 49 years.

When the company tried to raise the fare to 7 cents, they were disallowed by the courts because they couldn't prove the 5 cents fare was confiscatory.

I understand the city could raise the fare to benefit the company, but that isn't their obligation.

I would assume you're libertarian from the point you've made, and am curious whether you believe it was right for the contract to be enforced as it was agreed upon.