Not really, it could be that the great filter is apathy and single world habitation for instance - maybe we've been really lucky in terms of asteroid collisions so far and putting our eggs in two baskets is the necessary step for survival.

We don't know what the filter is, so it's sensible to reject pessimism and just keep on trucking.

The alt text on https://xkcd.com/893/ fits really well here:

“The universe is probably littered with the one-planet graves of cultures which made the sensible economic decision that there's no good reason to go into space - each discovered, studied, and remembered by the ones who made the irrational decision.” -- Randall Munroe

And I postulate that "The universe is littered with one-planet graves of cultures which made the sensible economic and game theory decision of having thousands of thermonuclear weapons pointed at eachother, hoping that MAD will make that whole bit of lunacy sensible." -- vkou

It's got about as much empirical evidence to back it as RM's postulate. (And a similar sample size of N=0)

Anyone care to get on the train for my pet issue, and get around to nuclear arms reduction, already?

The beauty of making arguments, based on observing experiments with a sample size of N=0, is that you can argue whatever the hell you want.