Now, a new part of the story had been added: One in which the cults of Cronus and Rhea have retired and the new gods reign supreme. From the way that Cronus swallowed his children to prevent them from coming into power, it can be assumed that there was much backlash against this new religion at first and the Indo-Europeans probably staged a violent invasion (hence the Titanomachy). But as usual, the new ways prevail.

I'm a bit skeptical about attributing aspects of mythology to a "violent invasion" of the Indo-Europeans - which was really more of a series of waves of migration over several centuries. Among other reasons, it doesn't account for the striking similarities between the generations of gods in the Theogony and several pieces of Mesopotamian mythology, particularly the Kumarbi cycle (Hurrian) and the Enûma Eliš (Babylonian).

I recommend taking a look at When the Gods Were Born: Greek Cosmogonies and the Near East by Carolina López-Ruiz and the marvelous The East Face of Helicon: West Asiatic Elements in Greek Poetry and Myth by M.L. West, who discusses Hesiod and the Mesopotamian parallels in chapter 6.