There is certainly less of a threat. But imagine what a small fraction, say a few dozen thermonuclear bombs, a couple SLBM's worth, would do to major population

There is certainly less of a threat. But imagine what a small fraction, say a few dozen thermonuclear bombs, a couple SLBM's worth, would do to major population centers and the economies they power. That and the after effects would be enough to call the continued viability of modern civilization into question. Nuclear weapons remain the surest way to end civilization on this planet, and the chances of that happening are far higher than, for example, a meteor strike.