We aren't talking bargaining here. The facts would be $1 billion. The point is that it would be something extremely valuable and reasonable that the vast majority would think is a fair trade. With a life on the line, you do what has to be done.
Your original scenario was a very generous offer and, if refused, taking the good by force. I don't think either individuals or a government would really be willing to offer so much in exchange. They don't really do whatever has to be done if it hurts themselves (even if exchange for a gain), they're more often willing to hurt someone else than bear a smaller increased cost themselves.
Even if they were willing to offer that much, if they used force on being refused I think they later would gradually offer and less and less so using force would also get less and less justified.
We know that on Earth, there is a severe energy crisis due to natural resources being depleted. That would certainly indicate a bad quality of life for Earth's people.
I think Cameron was implying and complaining that humans of the future and, implicitly, the present and near-future, were facing shortages because they had been indulgent or at least far from conservationist for a long time and the crisis for the bulk of the population would be much alleviated if the government imposed more conservation and redistribution but chose not to.
Imagine if Anij had come out and said out loud what's implicit in all this: we've got ours and the rest of you can suck it - we don't care about anybody else and we're not going to share or compromise.
I'm not sure what compromise the characters could or should have pursued, especially after the initial attempt was to secretly take them away from their planet. An obvious compromise, which Picard advocates and assumes the Baku would accept, would be for the Son'a to have and live in an other part of the planet; the Admiral says they wouldn't be willing to do so and that other species also wouldn't want to. It apparently could be a great benefit for billions but hardly any of those billions would go to the inconvenience of moving to get the great benefit.