I recently came across this New Scientist (subscription) interview with Thomas Homer-Dixon. In the interview, Homer-Dixon talks about his book The Upside of Down: Catastrophe, creativity and the renewal of civilization. He mentions his ideas for replacing the the perpetual growth/economics of scarcity model with something that is more sustainable.
Here’s an excerpt:

Isn’t there another problem, in that solutions may run counter to our economic model, which relies on perpetual growth?

Yes. In rich countries we need to figure out if there are feasible alternatives to our hidebound commitment to economic growth, because it’s increasingly clear that endless material growth is incompatible with the long-term viability of Earth’s environment. We need to know what a “steady state” economy – one with a roughly constant output of goods and services – might look like. What economic and ethical values might it have? Could it include some (albeit radically transformed) version of market capitalism? Would it be compatible with personal and social liberty? How would the political and social conflicts that would inevitably arise if there were no growth be resolved? Breakdown will discredit this economic rationalisation and create intellectual spaces for new ideas. But this space will be brutally competitive and might throw up rather cruel scenarios. We can boost the chances that humane alternatives will thrive by working them out now and disseminating them as widely as possible.

Could the process that spawned Wikipedia and open-source projects even help produce these humane alternatives?

Yes, I think so. What’s interesting about Wikipedia is that if someone had said 15 years ago that you could have a volunteeristic process, gathering knowledge to produce an encyclopedia which is almost as good as the Encyclopaedia Britannica, people would have laughed. I know there are teething troubles but the Wikipedia people are working on them. The details of the structure of open-source architecture will determine these projects’ success.

(end quote)

It seems like the economic model that Homer-Dixon is grasping for here is a “Commons Based” model. Because, basing economics around a commons base assumption is explicitly acknowledging that perpetual growth is not always possible or desired. I think the same (or even better) quality of living, and same freedoms can be obtained with commons based economic models.