Some suttas refer to places in India where past Buddhas dwelt, in one of the Buddha sits down on the same spot as a previous Buddha, to the joy of Ananda. In MN19, we also have a reference to a small fragment of a Dhamma verse spoken by a previous Buddha and remembered partially by the brahmans (“the greatest of all gains is health, Nibbana is the greatest bliss”). I always loved this tiny anecdote, it’s mind-blowing.
So to me it sounds like previous Buddhas appeared on Earth and in particulalry in India, a sort of spatial cyclicity. But how is this possible knowing the age of the Earth and of human civilizations? Maybe the model of the theosophists could have some truth. In their theory, the universe is continually destroyed and recreated (in line with the DN suttas), but the solar system is also destroyed and recreated continually. According to them there were many generations of our Earth. And maybe (this is not mentionned by the theosophists I believe), the continents and a country such as India are also recreated more or less in the same way… This model could explain the facts that the Buddha appeared on Earth and in India since a long long time: because our Earth is just one iteration among many previous and future Earths.
Note that India has a very peculiar geological history! It was attached to Madagascar at the beginning of the Tertiary and then detached itself and drifted through the Indian Ocean until it collided with Asia 10 millions years ago! Among tectonic plates, the Indian plate is one of the wildest one. The collision created ranges of mountains all around India: natural barriers that have offered a great protection for the civilizations emerging there… (/tin foil hat on: it sounds almost intentional! /tin foil hat off )