In theory, at least, the elastomers in the suspension can deteriorate over time, particularly if exposed to ozone and other such pollutants. But, I've heard plenty of cartridges in the thirty year old range that sound fine and have not suffered from such problems.
Way back in time, I had Shure cartridges that did not seem to last that long even though I was careful with setup and kept my records very clean. When inspected, the report I got was that the stylus looked almost new, so what I was hearing was either the suspension going bad or stylus wear that was not that easy to see. Whatever the cause, I have had MUCH better luck with wear with my MC cartridges (good thing, given the MUCH higher prices).
Aside from accidental damage (by far the biggest cause of cartridge failure), most of the better MC cartridges seem to last a very long time. Most of the non-accidental premature death that I've seen had to do with internal wiring failure (evidenced by one channel going stone dead).
