Resident Parking

Why do I pay for a resident parking permit year after year when there is no enforcement?  There are too many times that I can't park on my own street because there is no reinforcement.  If I were a visitor, why would I park in a garage when I can park for free in neighborhoods?  I also see out of state cars with guests permits for months at a time, these are clrearly roommates shirking the permit process.  If only I lived near the courthouse there would be parking enforcement!