A sustainable lifestyle requires a set of values other than ones based on greed as the driving force for individual actions, on economic growth as the ultimate goal of societies, and on material consumption as a measure of individual accomplishment.
Economic growth is not the solution to all social problems.
Overconsumption is the result of a growth-oriented and greed-driven economic system that both controls and caters to the frivolous wants of those who are able to pay.
Overconsumption leads to ecological scarcity (depletion, pollution, disruption of nature) and to existential scarcity (injustice, stress, alienation, crime).
Redistribution of wealth and control of population, rather than economic growth, are the cures for poverty.
The free-market economic system optimizes allocation of resources, but does not assure a sustainable scale of resource use nor a just distribution of wealth.