Since I've been smoking a pipe, 2011, there has always been an issue obtaining Balkan Sobranie, Esoterica blends, Germain blends, and a few Butera blends. Nothing has changed with those blends, and I don't see it ever changing at this point.
I know that when the FDA was going to impose rules about cigars and pipe tobacco (several years back, 2016?), which would requiring manufacturers to submit samples for testing, etc., many people went out and bought a tone of tobacco. Especially since they thought many blends would disappear. Then there was the closure of McClelland, and while many people bought up what they could of their stock, they were also buying other brands as there was a fear of other companies potentially doing the same. Then the same went for when Dunhill tobacco went away. Stocking up on Dunhill, and other favorites. I remember going online and literally every Samuel Gawith, Dan Tobacco, Wessex, and Rattray's, were out of stock, and most Cornell & Diehl and GL Pease blends were hard to come by. It was very difficult to buy certain tobaccos for a while.
Of course, then there were issues with distribution with Covid-19, and I think the tobacco companies are still trying to recover from that. Plus, I believe there are more pipe smokers currently than there has been in a while. So, between distribution issues, more people smoking pipe tobacco, and more people stocking up on tobacco, it's been harder for these companies to keep the shelves stocked.
That's just my thought though.