No, I am comparing the "evolved-from-former designs" to "former designs". So, it's not apples and oranges; It's heirloom apples and GMO apples! In terms of what designates vintage drums, one needs to determine when those designs changed, in a significant way. In other words, when did apple growers start genetically-modifying the seed? Well, IF there is a specific date for that, then that date is the 'line' for determining heirloom from GMO. In terms of drums, you ask yourself the same question: "When did American drum manufacturing significantly change the way drums were made? If there is a specific date or timeline when that happened, then that is the 'line' for determining vintage from modern. Free trade and OSHA...'nuff said! :)
So based on your own definition, a 1963 Corvette really isn't vintage because its construction and design parameters are completely different than a car from 1915. I don't think you really mean that. Drum sets in big bands, starting in the late 1930s, began to look more similar and have more in common with the drums being made today then they did from drum sets from the early 1930s and before. It is an innovative and evolutionary process and it continues today. To suggest that there is a time frame that we can point to and say before this time is vintage and after this time isn't, completely ignores the evolutionary nature of the changes that took place. What makes one item vintage and imbued with certain qualities that make it desirable vs something else that is just merely old, is often based on subjective desirability and not measurable objective parameters. In other words it comes down to personal perception. The old adage comes into play, "one man's junk is another man's treasure".
The 2004 Gretsch BroadKaster bop kit with gun metal hardware, with some of the last of Gretsch's Jasper shells, which my son recently sold, will almost certainly be a vintage collector's item in another 25 years. It already is desirable. He sold this 14 year old set, which he gigged on quite often over the years, for more than we paid for it. So will my early 2000s Fibes chrome over fiberglass snare (like the one used by Buddy Rich), and my signed DW Craviotto snare from a few years later. You may or may not care for these designs, but age and condition, as well as desirability and availability, will drive the vintage market as it always has. Heck, there even continues to be thriving market in collecting vintage utility pole insulators. I bet nobody saw that coming.