Your mistake is leaning on the mythology, having, it seems, not actually listened to the songs and stories yourself, directly.

There is no coincidence - the song lines record real geological events, such as the lowering of the oceans, the formations of islands, the drying up of lakes - on an ancient timeline - all of which are verified in the geological record.

Please, do not lean so hard on the petard of treating this subject as one of methods and coincidence.

These are real cultural artifacts, which encode real events.