>But of course, if you want stuff other than just not working, then you need to come up with a way to get that or have someone get it for you.
Indeed - and that mechanism is typicaly simplified as money. And since most people are working 40-60 hour weeks that greatly deflates my bargaining power for compensation - the labor market is flooded.
Just for the sake of argument lets suppose I was elected God for the week, and cut the length of the work week in half, along with doubling all pay rates so that everybody makes the same amount of money as before despite working half as long. And banned any preferential treatment for people working multiple shifts on pain of damnation (What? Where's the fun in being God if you don't get to dish out some hellfire?). What would that do?
First off you'd need to pay twice as many wages for the same amount of labor, so the labor costs of every good and service on the planet would roughly double - the capital costs however would remain unchanged, so depending on the particular good or service the point-of-sale costs would be somewhere in the range of 100-200% of normal. Let's say 30% of the average purchase is labor costs - double that and the average item then costs (.7+.3*2) = 130% of normal. That means your buying power from working a single job has has been cut to 1/(130%) = 77% of before.
Certainly everyone could start working double shifts to launch themselves to 144% of their previous buying power, but I'm betting a whole lot of people would decide that effectively earning 77% as much while halving their workload is actually the better deal. And if 10-20% of the population was happy with one job unemployment would vanish almost overnight as the market scrambled to fill empty shifts.
If *most* people were content with one job and a reduced income things would start to really improve - the labor market would be dramatically slashed, and the law of supply and demand means that wages would rise across the board as businesses compete for a limited labor pool. Hard to tell where things might end up, but if we were to assume another doubling in hourly wages we'd be talking about increasing the average item cost to (.7+.3*4)=190% of present, while the average single-job earner would be making 200% of present, for a 5% increase over current buying power despite working half as much.
Of course more advanced automation would also become more cost effective - but the price of that is in free-fall already, so I doubt it would make much difference in the long term.