As best as I can see, there is no magic bullet to help mitigate this.

At a minimum, I am convinced we need to update the documentation to describe this behavior on MacOS and recommend alternatives.

I continue to give serious thought to the idea of changing the default start method on MacOS from fork to spawn.  This would be a breaking change though one could argue MacOS has already undergone a breaking change.  Is such a change warranted?

The alternative (which does not seem all that appealing) is that we start encouraging everyone to first consider the start method before attempting to use multiprocessing even for their first time.  Providing sensible defaults is to be preferred, but changing the default to reflect a non-trivial change in the underlying platform is still not to be taken lightly.