A highly motivated vintage Mac owner might sort through old CRTs (if he can find any) looking for a compatible inductor. Similarly for gluing the bits back together, or salvaging slugs from other hunted-down coils.
The average vintage Mac person is probably willing to do some soldering repair, but isn't going to accumulate a junk yard in the garage in hopes of finding a compatible part. I think offering either a pre-built part, or a ready supply of the components needed to wind his own, makes it much more likely that old analog boards will be repaired rather than junked.
I've been hunting these components off and on for about two years. Most folks aren't going to spend a similar amount of time to fix one old machine. (Although it is true that I have a very small Duty Cycle for said hunt.)