Does the quality of an older interconnect degrade the sound over time?

The contacts will most likely be oxidized, but you can clean them.  I highly recommend cleaning the contacts periodically on cables and jacks.  It does not take very long for it to build up.  If never cleaned, all of your cables are probably pretty oxidized.

Really great advice.  I haven't cleaned them in at least 10 yrs, if not more.  Miller:  I've never done any of what you suggested!! No bueno.   I will be in for a surprise.
Thanks!

$275 for the Talisman?? Overpriced option indeed.

Yeah, clean the connectors every year and you should be fine. No deterioration in sound quality, I use at least 20 years old speaker cables. Not sure about 50 years old cables, it probably depends.

Agree with everything above. If it sounds good leave it alone. More than likely after 25 years your hearing isn’t what it used to be. My hearing isnt bad and actually I think it’s fine but I’m sure it’s not what it was 25 years ago.