That's not a scarcity problem but a scarcity of luxury problem.

Scarcity of luxury is by definition a subset of scarcity, so it is a scarcity problem.

Sure, we could all live on beans on rice, but people don't do that unless they have to.

But Greenspun's claim is that technology has done nothing to ease Malthusian limits, and he's wronger now than he's ever been. At the time Greenspun wandered into this fray, the concern was over human starvation. The situation really is much, much better, to a degree that is hard to fully appreciate.

Don't worry, they won't eat more than what is produced.