Larryi,
You're scaring me. Are you saying that some premium manufacturers charge a premium for older digital CD technology because older CD digital technology is better?
I love antiques myself. Antique technology may hold value for historical and collectible reasons but when someone tells me that older digital technology is inherently better than newer digital technology, something doesn't sound right.
From my equipment and listening experience, I believe that most common stock CD players today are way better than high end players from 10 years back or more.
Though any digital format, like CD, must have some inherent technical limits, whether realized in practice or not, digital playback is one area that should continually benefit from new technology innovations and the cost benefits that come from marketing successful new technology products over time.
Multi-format DVD players are perhaps more popular than CDs these days. Perhaps that is where the current advancements are occurring most rapidly and catching up or perhaps even surpassing that of pure CD players?
Very interesting topic and discussion, by the way!