Carl,

If "singleton" is to be defined that broadly, then we are already in a singleton, and I don't think anyone will object to keeping that feature of today's world.

Note that altruistic punishment of the type I describe may actually be beneficial, when done as part of a social consensus (the punishers get to seize at least some of the miscreant's resources).

Also note that there may be no such thing as evolved hardscrabble replicators; the number of generations to full colonization of our future light cone may be too small for much evolution to take place. (The log to base 2 of the number of stars in our Hubble volume is quite small, after all.)