IMHO we have hit the high water mark for 1960's era kits and are on the downside. Think about the age factor.....early 1960's was right at 60 years ago!!!! Teens of the era are passing and collections are coming on market.....a market that is slim at best. My best buddy got 4 models off ebay in the last two weeks that 20 years ago each would have sold for more than he paid for all of them. Good unbuilt kits.
It happened 20 years ago with Lionel trains....huge collections came up for sale as owners passed.....market demand was low....prices fell like a rock. The model values, for the most part, have not hit bottom yet. I have 5000+ kits in the stash......lots of guys do....when these all come to a small market......ugh