There's no distortion in the inner grooves when playing the old FR cartridge.
An improperly set up cartridge that is brand new will have distortion in the inner grooves also.
Closer inspection using powerful magnifying glass or jewelers specs would show obvious stylus wear, especially on either the right or left side of the tip, indicating that the cartridge was mistracking for quite some time.
The cantiliver they say can loose it's stiffness over time , but so far after 20 years the FR is still strong.
Dropping the arm on the record not lowering, and tracking at too high a range can lead to cantilever fatigue in a brand new cartridge.
If everything is set up to spec and there have been no mis-haps,and still lp's just don't sound as good as they once did, time to invest in a new cartridge and make sure it is compatable to your arm and set up properly.
Most cartridges fail because somewhere along the way,an accident happened.