Those 'ol farts like me will remember that these sets were red-hot when issued and were run-up over $20 some 46 years ago!
Ha ha! What I remember as a young collector who began my journey in numismatics back in 1992 is buying '61 through '64 sets for $5 to $8 each!! I wish I had stocked up back then!
In the last three years or so I must have purchased 80 or more '64 sets looking for the holy grail. Found a couple of nice Kenny's, one cameo dime and not much else to brag about. About half were sealed but could have been moisturized sometime in the past. The unsealed ones still had the glue edge on the inside flap. This waste of time leads me to believe that many of these were probably searched. I don't think I lost money buying them, maybe broke even as I used them for trade or outright sale.
Most people who bought proof sets from the early 60s, 60 - 65, sealed the envelopes themselves after inspecting the coins inside, so as to protect them. The ones that are sealed are more likely than not had more than the original owner of the set.
I agree 100%!!! It kinda takes a lot of the fun out of my hobby when I constantly have to worry about whether or not it's worth more today than yesterday.
If I was in coin collecting for the investment, I would have taken up a different hobby! Sure, it's nice to have whatever I own increase in value, but I put the money I want to invest into a savings account or IRA. My numismatic pursuits are purely for recreation. Positive movement of my money in coins is icing on the cake!