Even if they manage to reverse it, it would be over.
The longer "us" uses humanity, the worse it gets if you think about it. Supply chains are over, food production is already low enough that "us" expects millions to starve, the food that it's used it's not something a human would consistently take if they were an individual. Many world leaders seem to be gone, and humans have been shuffled around the world.
If this thing is reversed a new chaos would start, no one would be at their point of origin, there wouldn't supplies for everyone and the whole system that manage to glue civilization wouldn't even be there at the start. I don't see how any country could regain itself, anarchy would be the norm for a lot of time without mentioning the famine that would follow and as I said before the longer "us" is there, the worse is gonna get.
So in the end, the known world of before, it's pretty much over, and although humanity would survive in its individualistic form, more millions would still die in its transition from being "us" and the world would not be the same anymore.
I still think is the moral thing to do, but on paper if this is the ending the show wants to get, it should be bittersweet.