My guess (and I don't know) is that most signatures from the industry would have little recognition factor in ten or twenty years. Jim McEwan may be well known today, but who was the master distiller at Bruichladdich or Bowmore in 1986? Signatures of people who are no longer famous might detract from the value.
Scarcity is also an issue. I have a bottle of House of Commons whisky signed by Mr Tony Blair. Whilst this is clearly a nice thing to have, there are lots of similar examples out there and they are unlikely to be drunk, therefore as an item of value, my bottle has lttle value now and will have less value when Mr Tony Blair fades into history.
I collect signed books and do get them dedicated to me. I have no intention of selling them, but persuade myself that the more writing in the author's hand, the better. Even if it is personal.
I guess there is no right and wrong answer. Fashions change and the winners (financially) will be those who managed to guess the trends of tomorrow rather than follow the fashions of today. Who knows - Tormore might become a cult whisky and the man with a crate of today's vintage will be laughing.