I think a number of those rubber thingies have been lost over the years, it is annoying, you start to find yourself gambling over which keys you use the least.
I had the problem on an FM and when I bought an STE I also invested in some extensions for the ports (as it mostly happens when you start to push and pull the connectors when changing joystick). It is easy to make them and you could probably get away with 9PIN Serial extension leads (although mine are only 6 inches, although they say they is the national average).
RE: Broken joyports...