In general, most of your points are valid, though I'd say many people hop in a ship and center for fun rather than money payoff. That doesn't change your conclusion much, though. We could change powerballing to only have goals in the center and shut off at pop=10. Putting them in the center would decrease time (increasing DpTS). The major issue with setting the zone to work with low populations means that secondary pub arenas become a breeding ground for tradekillers. Historically, that's why we have the cutoffs in place.