It is really worthwhile to look at the first and second laws of thermodynamics and whether one should consider the biophysical reality of entropy in the context of economic growth.
But, generally speaking, economic growth is a human construct that uses the theory of infinite substitutability to deny any Liebig type limit. Not only that, but the prevailing economic theories ignore the externalities of production through a very liberal application of ceteris paribus as well as discounting the value of the future.
While much of this seems patently ridiculous in terms of the physical, chemical and biological laws of nature, infinite growth is a hypothesis that has a lot of appeal at a political level. To decouple from the growth paradigm would almost certainly immediately cause a global economic recession that would have very similar impacts to the actual effects of non-substitutability. There may simply no other way to sustain the wants of the current population.
The other part of the answer lies in the ability of capital to promote the interests of capital and pevert our social and cultural value systems. Modern propaganda, tries to teach us that the seven deadly sins are in fact virtues, that fiscal profit equates with social profit. Greed is good and economic self interest is the new political capital.
Because of this, and a number of other factors, the individual will to self sacrifice for future generations and to acknowledge limits to consumption simply does not exist in an enlightened democractic majority. The majority prefer to believe that everything will keep getting better and this is the message the political class sells.
