> It occurs to me that another solution is to keep the work force, but double the work
I think one other solution is to keep the work force, but double the output. I think this also happened (in addition to the other two that you identified). The overall productivity and output of society has massively increased.
And, of course, output doesn't have to be number of bars of soap.
All of the automation I'm familiar with is making the design and manufacturing processes more fluid, giving faster iterations at reduced cost. This allows the tech/process/whatever to progress faster. You'll finish your product sooner, but that means you can start the next sooner.
This whole concept of having more time assumes there's nothing else to do. There will always be something to do if you're not making something static, like soap.
I think one other solution is to keep the work force, but double the output. I think this also happened (in addition to the other two that you identified). The overall productivity and output of society has massively increased.