In the universe of the Instrumentality of Mankind, Nostrilla is the only source of “stroon”, a drug which indefinitely delays aging. “Stroon”, in fact, is “a virus that grows on enormous, gigantic misshapen sheep”, sheep who are diseased.
Instead of a dying Lamb that offers resurrection life, these are diseased sheep which offer an infinitely delayed death. In other words, perhaps Smith’s story is, in part, an answer to this question (which perhaps no one else has ever asked): “What if we had diseased sheep instead of a dying Lamb?” Diseased sheep keep producing “stroon”, this gives rise to the possibility of harvesting, which gives rise to the possibility of a market, which gives rise to a need for a monopoly, and defences and weapons to maintain that monopoly.
But a Lamb can only be made dead once (well, depends on who you ask, I guess).