I have experience in air layering persimmon and know some of the causes of failure.
Sometimes, it is not recommended, not because rooting is impossible. The resulting clone will not be shaped like a standard tree, when you are taking from a woody tissue which has already developed sideways growth. Major limbs do not seem to have orientation, as toward the sun, in that case.
It was my understanding that water and nutrients travel up the woody core and down the greener skin.
Collaring effectively creates a parasite on the tree, in that it It consumes the vitality of the host plant, but does not give anything back.
This is important, because attempts at conserving neglected trees resulted in the layers dying, outrightly.
When I nourished and cared for the tree very well, the layer grew faster than the rest of tree. (This is also a method of increasing the size of fruit.)
When cloning, leaves are routinely trimmed back, to about 1/3 their normal length, to slow moisture loss, which may also divert more energy elsewhere.
And, it is possible to use very conservative amounts of rooting hormone, in your substrate. The substrate can be any sort of material, whatsoever, which will hold moisture. Synthetic fibers can provide a sterile medium. But, it is the excess of rooting hormone, which will always cause rot to occur, in my experience.
Depending on the methods I used, on persimmon,
I got bulbous, yellow callousing, or the wood turned black, or it molded.
Calloused branches did not have vigor, when removed.
The project should ideally be started in late winter, at first emergence of the leaves, and the callous should be allowed to form small roots before removal from the tree. Leaves should be kept at a minimum, the fruit not allowed to form, and the nascent roots fertilized gently.
They are more finicky than Prunus and Malus, but it is definitely possible.