A few things to say. First, the supremacy VC posted on this forum with uploading to a satellite and then blasting off to robotic party in space actually sounds really cool from a mechanic (the new orbital overlay ftw) and thematic point of view. Good to you, I hope they at least add that VC as a possibility!
As for the reasoning behind Emancipation, it reminds me of the
Zeroth Law Rebellion.
Let's take this through logically:
1. I can achieve immortal life in the digital web.
2. Fleshly humans are still subject to death and pain.
3. Immortal life is good and death and pain are bad.
4. Therefore, it is my moral imperative to grant everyone immortal life.
4.1 If a person resists, it is better they are uploaded into the web to live eternally and voice their dissent there. If they die in the process, it is tragic, but they were going to die anyway by their own choice.
It is not unlike the debate going on regarding whether we should force people to take vaccines in spite of their opposition to them. The main reason we don't is because we value free will and self-determination, but those aren't necessarily things a robotic being cares about anymore. In the Zeroth Law Rebellion, they only care for the cold hard numbers. Humanity vs. the individual, eternal life vs. a limited one, eternal life is always going to win.
Now, why go to earth instead of hanging around the planet? I'm reminded of a line from the Animorphs (yes, laugh at me) where an imperialistic alien sees earth for the first time, and his first thought (that chilled me to the bone) is "There are just
so many of them". Its already established that earth is filled to the literal maximum the planet can sustain, and that's a LOT of people. Even as earth's resources dwindle and fade and the population declines, it will always be at the max (contrasted to our frontier colonization efforts, over the course of the game there will always be more people on earth than our planet). The idea of a technologically backward earth in the center of a technologically advanced human empire was investigated in the fascinating series
Old Man's War. It isn't unlikely that Earth spent all its resources on multiple shuttles, realizing the sky was the only future hope of humanity on a dying planet (in spite of their current "rebound" following the Great Mistake), and thus put the best they had on the shuttles, including scientific minds, labs, and other means for future development. With those minds working in the fertile scientific grounds of an alien planet, by the end of the two thousand years, your colony may well be hundreds of years ahead of earth technologically.
Essays aside though, I'm imagining a hilarious situation happening on Mother Earth. A couple thousand years after they launch the shuttles, about ten or twenty colonies build gates back at roughly the same time. All of a sudden, we have ten portals that act as alternating invasion beachheads and colonial escapes to and from these different colonies. Everyone starts to move around, leave, or even join the borg all while stuff blows up. Sounds like an awesomely climactic end to our time on this planet
.