A few thoughts on paying for stuff.

Capital mobilization is a key problem for standard capitalist economies (it's in the name), and so it must be for us. I encounter this problem routinely when I am trying to articulate the sustainable alternative. How do you pay for it? 

First of all, in the experienced world where bio-physical limits don't do marketing to get attention, people don't experience any  boundaries between what is  sustainable and what is not. All they know is the world is or is not comfortable. So any effort to constrain economic activity within the boundaries of "sustainable" (such as the efforts to reduce fossil fuel consumption) will be met with skepticism, or worse. And anything that constrains the flow of capital and therefore constrains comfort will be resisted. We need to disentangle comfort from wealth.

My argument has been "You can be poor and lead a rich life". The problem is not whether the economy is burning through enough resources and providing abundant material goods, the problem is whether people have access to the things they need, including health care, education, housing, a rich social and cultural life and opportunities to learn, grow and pursue status. Material wealth does not replace the social rewards which give meaning to life, and we can reduce that flow substantially without harm to quality of life. Conceivably a sustainable economy could function with less money flowing through it, but the rewards of comfort and a rich social life would exceed current levels. 

Another hugely significant factor is the gross imbalance in wealth as currently experienced. An economy could increase the well-being of those in the  bottom three quarters of the economy with a small fraction of the existing capital. The economy is constructed to provide the generation of new wealth (Oh what is money anyway?). Piles and piles of it accumulate out of reach of ordinary people. How much of that money is being used to produce actual value, and how much just grows cancerously to produce new, fictitious assets? (Lard on the economy that clogs the arteries of genuine economic activity.) So we have a money copier. As long as they don't try to spend it all at once, it holds its value. In other words, there is already so much money that we could never use it all! How much of that supposed value is locked up in property, whose "value" is really just what it is bid up to? A hell of a big pile of money would disappear if the upward pressure on the value of property were to disappear. Maybe we should be asking whether there is a tipping point, where the amount of available capital is so great that it begins to lose value? Maybe the economy should be spending down some of that excess wealth (prosperous times ahead!), doing some of the work needed to protect the health of the planet and bring people out of poverty. 

I imagine a world where the capital needed to fund projects is held by "middle-class" people. Instead of depending on an investor class to supply capital, we depend on the consumer class to be the investor class. I also imagine a world where the goal of economic policy is to drive everyone toward the middle. Our current system supports indefinite accumulation of wealth, actually taxing high wealth at lower rates than low wealth income. What if instead we increased taxes as the level of wealth increased? If you want a vigorous economy, tax and spend!