Do MC Cartridges Deteriorate over time

It depends on the hours of playtime, stylus must be retipped after 500-1000 hrs. If the damper is fine (you can check it) then you don’t have to worry about it. Most of my favorite MC cartridges are 35 years old, some of them still unused or even factory sealed, some of them are in use and sound quality is mind blowing compared to more expensive brand new cartridges.

Yeah, huge amount of high end audio sounds great in theory only to completely fall apart in practice. Like cartridges, the suspension should just get all hard and brittle and go to hell just sitting there used or not. But this never seems to happen. The Stanton 681EEE on my Technics from 1976 still works great, and that is a lot older and a lot cheaper than your Clearaudio. 

A good cartridge is like a good watch. Sure they will tell you it needs regular service. But in reality, If it ain't broke....

Suspension damping can change its characteristics overtime. With clean records I have seen styli last over 3000 hours. The only failures I have seen were due to failure of the coil wires at the solder joints. Copper will work harden so vibration at this joint eventually causes failure, This is the one big advantage of gold coils. They will never do this. I had a Sumiko Cartridge fail this way, a Talisman S. If it plays, tracks and sounds good to you it is probably OK.

If it plays, tracks and sounds good to you it is probably OK.

This^^^