You forget something though, if humans get the stretch/warp drive you can bet there would be a mass exodus from Earth to the rest of the Galaxia. Humans were uplifted and abandoned by all the current Sibling races and as such humans would have the right to go anywhere in the Galaxia for having once been their "children".
Humanity my very well be the mortar to bind all the Galaxia races together (I'm pretty sure that's part of the Parents plans since our race could never resist going out and exploring). So if we are out there, you can bet they would want to come to Earth, if only to visit. But plenty would stay simply because our planet has things that remind them of their own homes (ie. the Sahara desert is just like the entire planet of Khemia).
As for all your negativity, well that's your issue. But on the point of resources, once humans can reliably get into space and back we would mine asteriods and other space bodies and get more from them then we would ever get from Earth. Our solar system has millions of floating space bodies that could be mined, not even counting the existing known planets and their moons.
Of course the whole Avia Pox thing would need to be solved first.