Jay is going to answer your email when he returns from vacation but meanwhile I'll answer this question now as it's a bit more direct.
No chip ever has been an investment-grade asset.
Over the past 15 years the vast majority of prices have fallen anywhere from slowly to fast. Most values are now only 1/3 to 1/2 of what they were 15 years ago.
The very high end chips have suffered a lot less, it's true, but the number of collectors willing to buy those chips has fallen so there is less competition.