you can happily park on the street for free if you want as parking restrictions are normally 8AM to 6PM.
the problem arises when you have space for 500 cars, and 2000 drivers want to park there.
Charging and other restrictions limit the ability of some people to hog all the spaces all day, every day.
(this does not apply to the rich, who are happy to flout traffic rules as the cost of fines does not trouble them, which is why parts of the West End have very fast tow-away and lift-away systems).
