The idea that parking fines are a source of significant revenue is pretty bogus. NYC for example collects around $500m in fines while spending about $200m for the NYPD division of traffic control and another $270m for the Department of Finance (which collects the fines) and while these costs are not entirely dedicated to the purpose of issuing tickets, it gives you a sense of the scale of net revenues from parking tickets (low hundreds of millions at most) compared to a city budget of over $75 billion.
Parking tickets exist because public property in urban areas is extremely valuable and the opportunity cost of letting some scofflaw waste the space is enormous.
That's really, really lazy logic you're (not) trying to compute. If the send-your-enemies-glitter guy wasn't in it for the money, why'd he sell his site for money?
Also Chicago sold the rights in a fire sale due to some combination of budget shortfall, corruption, and incompetence. After the fact, independent appraisers found the contract should have been worth more than $2B, but was sold for just over $1B.
Parking tickets exist because public property in urban areas is extremely valuable and the opportunity cost of letting some scofflaw waste the space is enormous.