I think the correct usage, where applied to this collector market, in particular, would be those qualities indicated by RogerSling. Once mass manufacturing took on the look and feel it as today, he is right, drums all became generic, like the use of auto-hammers in cymbals changed them to a more uniform product, like them or no.
Let's take the Ludwig 6 ply era, for example: virtually all 16x16 floor toms from that era, regardless of wrap type, lugs (classic vs Std vs Mach) pretty much sound the same as the next one out of the crate, whereas 3 ply shells were much more affected, sonically, by cortex wraps, natural finishes and other factors.
The glue change at Ludwig, I think I read somewhere a couple of years ago, came about the time the scarfed in wrap ended, but before the end of 3 ply shells, the clear lacquer era? Or was that the Granitone era? I get those confused as to which was earlier or later, and even when the scarfing changed, but it seems the clear maple shells had no scarfed wrap.
Anyway, this is when the tones began to take on a more generic or "standardized" quality, the end of scarf jointed wraps, and more consistently round drums. And then the 6 ply Chicago and 4 ply Monroe shells, all sound virtually identical to their respective types, except the 4 ply Monroe in wrapped vs natural finishes...
I say we stick to the RogerSling explanation and go with it!
Afterall, it seemed to hit the big 3 all about the same time, and Rogers just exited, pretty much, when CBS started demanding absolute profit over absolute quality. That pretty much hit all the corporate structures at the same time, and mass production techniques helped to realize that factor, for awhile, until the Japanese, who already had the formula working for them, took over the rest of the market. Gretsch seems to have, for the most part, escaped a lot of the hectic corporate greed that all but killed the others.