The Vedic version is that the Aryan/Indo European population originated from the hollow earth, and settled around the Arctic rim, such as Scandanaia and Russia. From there they ventured down through Europe and Central Asia, especially after the cloud mantle fell and the foods came.
It seems that the mantle fell because of a change in gravity, which brought on a change in orbit, too.
What would be the reaction of the surface world if the hollow earth were suddenly to discover the hollow earth and find out the way things are inside? You know, people grow to be ten to eleven feet tall, they live for 800 plus years, an apple is the size of a man's head, et cetera. Would our reaction be a sobering up when suddenly faced with our origins? Lord of the Flies? You know, when the little kids who were stranded on the island had finally turned themselves into savages, killed one of their number and were chasing the other little boy down the beach to kill him, too; they suddenly came face-to-face with a British naval officer, some sailors and a British cruiser in the distance. Their reaction was basically something like "What have we become?!!".
Would our reaction be repentant in a similar way? I think not. I think our reaction would not to be to seek spiritual guidance, nor would we interest ourselves in returing to our cultural roots. Our reaction would probably be something more like "We'll stay the way we are, but all we want is all you got!".