My collection of FSM starts with Jan 1990 and its still in great shape. It may have something to do with how you store them. I keep mine in boxes that are in a closet. I frequently pull them out to use as references.
Remember, if they up the quality of the paper they may have to up the price too. My Jan. 1990 issue set me back $2.25. The good old days.
Good luck
Darren