We're more than capable of surviving in bands in the environments we're most adapted to. We could live like chimps if we had to, eating grubs and berries in a topical forest or savannah with rocks and sticks our only tools, like other great apes. Being human, we'd soon be improving on what we have so we can support our increasing numbers. It would be a hard life at first, but life ain't easy for chimps, either.
I'm not anti-Christian. I'm anti-stupid.