I have discs dating from 1985 (when I first started collecting CD's) and only one or two have shown any degradation. Only one deteriorated so much that I've had to replace it (Ozric Tentacles - Erpland on Dove records - the re-master from 1996 approx appears out of absolute phase and sounds "squashed" by comparison unless this is attended to...).
Modern CD's are *supposed* to be better, as machines made since the mid nineties don't like out of spec CD's, where it was almost a competition to get phenominal tracking of bad discs before this time...
Sorry to hear of the problems you're suffering. I haven't bought many new discs in ages as I can't really afford to and I have a huge LP collection to re-discover.....
Tear down these walls; Cut the ties that held me
Crying out at the top of my voice; Tell me now if you can hear me