The economic downturn has produced an explosion of popular anger against bankers' "greed" and their "obscene" bonuses. This has accompanied a wider critique of "growthmanship" – the pursuit of economic growth or the accumulation of wealth at all costs, regardless of the damage it may do to the earth's environment or to shared values.
John Maynard Keynes addressed this issue in 1930, in his little essay "Economic Possibilities for our Grandchildren". Keynes predicted that in 100 years – that is, by 2030 – growth in the developed world would, in effect, have stopped, because people would "have enough" to lead the "good life." Hours of paid work would fall to three a day – a 15-hour week. Human beings would be more like the "lilies of the field, who toil not, neither do they spin."
Keynes's prediction rested on the assumption that, with a 2% annual increase in capital, a 1% increase in productivity, and a stable population, average standards of living would rise eight times on average. This enables us to work out how much Keynes thought was "enough." GDP per head in the United Kingdom in the late 1920s (before the 1929 crash) was roughly £5,200 ($8,700) in today's value. Accordingly, he estimated that a GDP per capita of roughly £40,000 ($66,000) would be "enough" for humans to turn their attention to more agreeable things.
It is not clear why Keynes thought eight times the average British national income per head would be "enough." Most likely he took as his standard of sufficiency the bourgeois rentier income of his day, which was about 10 times that of the average worker.
http://www.guardian.co.uk/commentisfree/2009/nov/22/maynard-keynes-wealth-economics