And it's not just myth busters either; as history progresses, the cultures themselves develop different attitudes to what once were myths.
Take the annual flooding of the ancient Nile. When Sopdet, Sirius the Dog Star rose in July, the Egyptians knew the Nile was due to flood soon, so based their crop season on that cycle. They equated the star with Sopdet, and the flooding as the tears Aset shed when Set killed Wesir. Wesir, as the god of vegetation as well as the afterlife, died and was reborn in the grain every year, so Sopdet would rise and Aset would continue to cry, to bring life to the people.
Centuries later, the Suez Canal was built to manually control the Nile flooding whenever desired, to better serve Egypt's larger population. The symbolic cycle of the Egyptian myth was permanently broken, and the rising of Sirius was no longer consequential. People could have good soil for food year round. Egypt is a Muslim country, but I've never heard an Egyptian say that Allah's will determines the crop season.
Is there still truth to the myth after the culture progresses beyond what it represents? That's an individual's decision. The myth was a popular truth for some time, but you can now see it as a lie, or another version of the truth, or something in between.