My 5th-Wheel hasn't bee out of my barn for over 3 years, yet I have to pay the $65 registration fee each year just in case I do decide to go for a trip. If I fail to pay, then when I do pay it is from the day it was due. That's life. Time some of these whiners learn the facts.
Sorry but those aren't the facts. You are comparing your state gov't to a flying club. There are plenty of clubs that allow pro-rating or discounts for partial year memberships. I believe the AMA has the best and safest solution for memberships renewals. Keyword safest.