He picked the tobaccos to fit a specific metric in his head, and he did a LOT of processing, adjusting temperatures and pressures up and down the line. It wasn't a case of setting a bunch of presets. There was his art as a processor involved in it. And there was considerable aging as part of the process prior to releasing a batch. Even if he could have somehow written down instructions there was no guarantee that the same level of result would have been achieved by someone else, so they opted to shut down and retire.
I come from an area with alot of mom and pop pizza joints all who have their own individual style and we see the same thing when the owner steps down. The whole 'recipe' can be exactly the same but the technique of the hands making it is all the difference.
One place mechanized to conveyer ovens etc. It's unrecognizable. But when our county fair comes around the family makes it in a food truck the old school way by hand and it tastes just like it used to.
The other thing most people here don't realize is we smoke blends, not vintages. (limited/seasonals notwithstanding) That means a blender is trying his best to make a blend taste consistent. That means actually making it differently alot of times to compensate for different batches/shifts in quality due to farming issues, etc.
Any guy with 2 hands can mix together a few tobaccos and make it taste good. But can you make it taste exactly the same over a decade of droughts, surpluses, supply chain delays, supplier closures, different cure rates, environmental/storage condition fluctuations, etc etc etc