[Update: Looking for more parking policy information?
Try Reinventing Parking.]
So you think on-street parking is public property and should be free? Do you think local governments that charge for on-street parking are uncaring and money grabbing? Maybe you doubt that cheap on-street parking causes any problems?
Then please take a look at Bern Grush's vivid description of the "cruising for parking" in one specific trip and all the problems it causes.
The trip should have been 5km but searching for parking by driving in circles at the end made the journey 8.25km! And that is the least of the problems that Grush describes.
The image above is from the post at the Grush Hour blog and shows just that last part of the journey.
You couldn't ask for a better explanation of the need for performance-based pricing for on-street parking.