The energies from the Upwelling do not come in constantly: they fluctuate, in great cycles of thousands of years. The energies stay for a time, and then they fade.
When they are here strongly, it is a Golden Age for everything on the planet, a time of plenty and of magic. When they fade, the world becomes darker and darker, and magic is eventually lost entirely … until it returns again.
There is a concept in Hinduism of a cycle that our world moves through, with four ages in each cycle. This concept is based on the rise and fall of these same powerful energies in our world.