"Both Right and Left should aim for a productively employed workforce, that can pay enough taxes to make the books balance."
First question is: how do you define a 'productively employed workforce'?
There are two main economic theories, one followed by the 'left' and one followed by the 'right' as I understand your definition of those two poles. The left believe in the theories of Karl Marx and 'Das Kapital' and the right believe in the theories of Adam Smith and 'Wealth of Nations.'
Both are perfect economic models but only in theory and both have failed in practical terms for exactly the same reason: they do not include people in their calculations. As far as the theories are concerned, production of goods is of utilitarian value only. The produced goods have a value but the workforce does not have any value except in economic terms and are classed as 'productively' employed only on that basis.
The Industrial Revolution brought about the beginning of the machine age where machines took over more and more of the production process and the contribution of the workforce gradually diminished to the point where they ceased to be 'producers' requiring skills and became nothing more than machine minders.
"What began as a way of duplicating human skill on a greater scale will end by replacing skill altogether in order to produce goods regardless of any human intervention. As a necessary part of the process any call for the control of machines, however desirable in human terms, is bound to seem illogical since it amounts to the destruction of the system for generating the wealth needed to perpetuate the consumption that underpins the social fabric."
"Such is the remorseless pressure of this process that it becomes, in due course, a sort of cannibalism, first of all destroying the machine minder through automation then in a further step destroying the machine by an economy based on the virtual reality of computerised information. At this stage the question of human needs hardly arises, having been displaced by the internal demands of the productive system itself. This 'system' possessing no vision of an end other than its own perpetuation, must eventually bring about its own destruction."
The above two paragraphs are copied more or less verbatim from Brian Keeble's book http://www.goodreads.com/book/
The ideas of left vs right or socialism vs capitalism are obsolete because everyone now believes absolutely that the purpose of production (i.e. work) is as stated above. Endless growth and over-production can only end, not just in the system's own destruction but in the destruction of life.
In fact it can really be summed up in this video by Alan Watts (which I have referred to previously)
In reality the 'productively employed workforce' has been diminishing rapidly and will soon cease to exist.
What then are people to do with their time if work, as previously understood, is no longer an option? A life of leisurely boredom? I think not, "the devil makes work for idle hands!" as, no doubt, your granny would often remind you.
The unasked question in your post is "what is the purpose of work?" and that question will be addressed in part two.
The Reign of Quantity and the Signs of the Times
Revolt Against The Modern World
Art: For Whom and for What?
-Sir Edwin Arnold(tr)
A Guide for the Perplexed
-Ernst F Schumacher
La rebelión de las masas
-José Ortega y Gasset
The Perennial Philosophy
The Perennial Philosophy; a critique