I dont wont discount cultural elitism taking play to some degree in the general perception between the two

But that being said written records do allow the records to survive and be examined a bit easier. For exame you could start checking the historicity of something by seeing if someone else wrote about it. If say the Babylonian, Egyptian and Asyrian records all agree that an event went a certain way (especially when those areas were independent from each other. Seperate kingdoms dont have as much of a vested interest in telling the same story) all record an event the same way from roughly the same time period there's more credence to the telling. 3 seperate oral records are less likely (in general) to have come down through the ages than cuneiform tablets.

You could also potentially trace translations and versions of the story through time to see how it morphed and evolved in the retellings or when being translated. That would be something like comparing the dead sea scolls to a modern old testament/Torah. How much it varies overtime and what varies over time can give hints and clues.

Thanks for sharing that it was an interesting read! I guess with the right cultural carrots and sticks you could trust the story is being more accurately carried down the generations

To your first point, I alluded to that in the 2nd paragraph. To your second point, which link are you referring to? I did not see anything in the article about aboriginal storytellers unless I missed it

The "problem" with objectively believing folklore or oral traditions without any other evidence is that they are folklore and oral traditions. A story that gets retold thousands or tens of thousands of times is going to change slightly with each retelling. The broad strokes will obviously stay the same but the finer details may blur and bleed into each other. Even ancient written records will have this problem to a degree from all the copying, translating, recopying and retranslating (not to say anything about the biases of the storytellers either).

Ancient traditions and stories are certainly good jumping off points for investigation since there is likely some event or place they are building off of. Finding other evidence can start to untangle what makes a good story and what we can say with good certainty happend or existed.

Take the Illiad as an example. The Trojan war makes for a great story but most of it is likely fictionalized. There probably wasn't a Helen and the Greeks probably didn't launch a thousand ships to rescue her. But there's likely a good chance it preserves a memory of Greeks coming into conflict with Anatolian peoples in that region. Finding evidence of a city that is likely Troy in the modern era gives more credence to parts of the story having kernels of fact dispersed into the mythology.