Maybe parables are the way to tell a historical, metaphorical, and life lesson truth, in that it causes people to wonder and imagine as a child, without the disbelief that life so often causes to become a stumbling block. For the more learned, Jesus often gave the story behind the "parable" he told to the masses...and you know what, the story didn't change, nor the facts, just the imagery...Fair enough m8.
I think that some people just take things far too literally and they then discount the other aspects as they don't fit into their model of understanding.
Having spent many hours talking with relatives and others concerning christian matters I find this the norm (most people are literalists )
Yet Jesus himself said that if you don't understand parables you won't comprehend what he was getting at (my paraphrase).
Paul also said (concerning Abraham) that the work was allegory.
Case in point, parable of the seeds - seeds on a path became the words of redemption and salvation...the promise of a better life. Some hear it and forget it, some start to adhere to it, but are distracted by "reality", some find deep meaning in it and it grows and deepens in their lives, and the seeds spread from them to others they affect in life...
where is the falseness in that? Where is the non historical fact? Where is the mythology? None, none, and none.
Is it historically true? Ask any farmer for that answer...happens all the time.
Is it mythological? see question #1
Is it false? see question #1
The issue is the packaging, so that we can wrap our minds around what happened between us and this "Creator".
I think, if we knew the truth...it would kill us (within us, by our own will and devestation of knowing we sabotaged our own relationship with something so wonderful).