It's the shift to a service industry, too
Unraveling the individual effects could probably fill someone's PhD thesis, but combine the massive numbers of women entering the workforce, the export of manufacturing jobs to the Third World, and the automation of what jobs remain, and you end up with a lot of people waiting on each other. For an economy to survive, given current models, some has to actually make something. But let's extrapolate a bit ...
Farming keeps getting more efficient. Where once 50% of the population worked in agriculture -- 50% of the male population, anyway -- now it's down to what, 2%? So 48% had to find something else to do. Then we automated our industry. More jobs no longer done by people. Then we exported the jobs that couldn't be automated. Well, that just shifts the jobs around. Someone still has to do them, and that brings those people into our economic model.
But what happens when all the "needs" of a society can be met by 15% of its citizens? What do the rest of them do for a living? Sure, we'd like to think they can turn to the arts, and exploration. But who's going to give them a paycheck?
I think we've reached a point of industrial efficiency where we don't need so many people to work. We just haven't figured out how to divide the resources other than giving them to the people who do work. And of course anyone who wants more of the resources will try to work for them. In a capitalist society anyway.
So what's the next model? That's one of the questions Star Trek has always sort of glossed over. They refer to a time when replicators became commonplace, and the social and economic upheaval that followed. But they never really got into what model followed. I can't believe mankind is ready for "true" communism yet -- from each according to his abilities to each according to his needs -- but that's the only thing I can see working when labor isn't needed. That or Brave New World, with mandated inefficiency.
