[colanderman]

You are right. The other way is for a new, massive industry to open up. (Think terraforming Mars.) This would correspond to increased per-capita wealth consumption.

However the fact that you must choose four of {decrease excess wealth, decrease employment, maintain moderate per-capita consumption, maintain high per-capita work output, maintain high per-hour work output} is a logical truth.

Proof:

Wealth can be created (work), destroyed (consumed), or accumulated and held (income/wealth inequality). Wealth must be created at the same rate it is accumulated or destroyed (i.e. Wc = Wa + Wd). Since OWS wants to decrease wealth accumulated and it is undesirable to increase wealth destroyed (unless in the example given above), we must therefore decrease wealth created. Right now this is happening due to unemployment. Since OWS also wants to minimize that, we must decrease wealth created in another manner. Obviously, decreasing wealth created per hour worked is out of the question (that would mean reverting to a pre-industrial age). The only remaining option is to decrease hours worked. QED.