In another part of the galaxy, far far, away another discussion is happening about this very topic that contains some very solid information regarding the Burley issue. One little tidbit was reported crop yields for Tennessee Burley over a 20 year period. The projected crop yield for 2022 will be only 4% of what was grown 20 years ago.
For a variety of reasons - the marginalizing of tobacco smoking through "death by a thousand cuts", the loss of government support in the form of subsidies to growers, more profitable and less labor intensive choices of crops to grow, production is dropping in the US. If you believe what some of the blenders are says, quality is dropping as well, in part to cost cutting measures, such as automated harvesting rather than hand picking.
Certainly the evidence is there is the widespread "stealth" changes to blends. What's in the tin may, or may not, be what's on the label if it's a blend with a good deal of history.
Does that really matter. For me, yes, because I think that there's a level of dishonesty in continuing to label a blend with a name that isn't reflected by the contents. I get that it's monetizing the IP and I don't care nor respect that. Blends became loved and celebrated for what they were. Now, only the label is left.
The substitute blends may be fine on their own merits, but give them their own identity.
For a great many smokers none of this matters at all. They're buying the label, not the contents. If they're happy with the contents, it's all good. Thus for many, the stealth changes don't matter. If you like what you're smoking that's what counts.