After losing Magic, I had that familiar emotional reaction that goes "How could I even think of some other, inferior animal in the place where my precious, irreplaceable, once-in-a-lifetime pet used to be."
It helped me that Magic had been such a friendly, generous fur-person. Possibly she knew that no other animal could take her place in my emotional heart...she adopted kittens and tamed possums, and never minded sharing her place on my knee.
Nevertheless, I still had to bite my tongue and tell myself, "They don't need to be friends and partners like Magic. I need a cat for humane and efficient pest control. Cats need homes. There WILL be at least two cats here at all times...even if they're only dumb animals who don't remind me of Magic in any way."
With this mind-set I've managed to bond with several other cats. The combination of survival intelligence, listening to humans, nurturing kittens, and sociability that made Magic special may not recur within my lifetime...but I'm surprised by the number of cats who have at least one of these traits to some extent.
By now, if nothing else had happened to her, Magic would have died of old age. I would have had to bond with other cats anyway. And I'm glad I did it right away.