[Evolved]

I have paid for all those luxuries.

Car = I paid for it out of the money I earned

Roads = I pay for them with my taxes

Parking = I pay for this either by being a customer of your business or, if you're a landlord, by paying you rent every month.

Making free parking into pay parking or making pay parking into more expensive pay parking will serve to decrease traffic, but at what cost?

Once you monetize it or make it more expensive than a reasonable price it practically begs to become corrupt. The end result is only incentives to increase parking costs via tools such as premium/VIP parking. Theoretically, a premium spot could pop up and would normally be a regularly priced spot when the inventory of other spots dwindles. The spot itself isn't actually any closer to the destination for the customer but is just more expensive. Sure, you could argue that this is how supply and demand works but that only really applies to supply of goods for which there are similar alternatives. If you raise prices on parking, why not raise prices on public transportation as well, and if you're raising those prices then who is going to stop the taxis and ride-hailing apps (Uber, Lyft, Sidecar, etc.) from raising their prices as well? You haven't actually solved any problems. You've just made more money.