The problem is that more societies are joining them. In a vacuum its good (for some values of good, since there are real problems with declining population) for

The problem is that more societies are joining them. In a vacuum its good (for some values of good, since there are real problems with declining population) for all populations to stabilize, but if poorer countries reach population equilibrium (or slight decline) while also consuming like the USA, then we're net behind. The nonhuman biosphere doesn't really care about per-capita consumption and emission, just the overall amounts of each.