It may not even be a problem at all.
That is, in light of the massive revolutionary effects of automation and robotics that is happening as we speak, as we can see here, here and here.
It is potentially so revolutionary it is rightly being dubbed the “fourth industrial revolution.”
The warning signs have been here for years: e.g., a 2013 Oxford study suggests that about 47% of human jobs will be lost to AI by 2030. First, working class and then middle class jobs will be hit.
When, for example, machines can do the work of people in fast food restaurants, what sort of world will result for low-skilled and semi-skilled workers? Even offshoring will become pointless, if production by machines costs less than third world labour.
And don’t trust halfwit neoclassical economists to provide sensible analysis here, because their response is almost always that only if you make wages become flexible and rely on laissez faire market theology, then this will eliminate involuntary unemployment. That is rubbish. There is no reason to think a fantasy-world self-equilibrating market will solve the problem of mass unemployment, because it does not exist.
At the very least, all this suggests that the endless hysteria about shrinking working-age labour forces in the West is grossly exaggerated. If anything, fewer workers mean less of a problem with mass unemployment in the future. More likely, there will be plenty of people to look after the elderly and do whatever necessary work is left to people.