We desperately need these "full-world" economics - or full-accounting economics - or holistic economics (we need a good name too...) in order to show that a lot of current discourse on growth and propserity is nothing but.

In the long run, we're all dead. John Maynard Keynes

... in the macroeconomic labor productivity, the ease or difficulty of getting more goods and services is whatever it is. Its easier to achieve labor productivity gains if the empty world assumptions are closer to being correct, and harder to achieve labor productivity gains if the full world assumptions are closer to being correct, but at the macro level, what it is is what it is.

Where the empty world assumptions comes around to bite the traditional marginalist economist on the buttocks is in dipping down into the conventional marginalist micro-economist to provide an underlying model of how hard or easy it is to achieve labor productivity gains. This activity goes under the heading of "putting the macroeconomic model on microeconomic foundations".

Even there, it is possible to assume absolute caps on material inputs, however it is analytically inconvenient, and the convention in traditional marginalist economics is to only assume analytically inconvenient things if absolutely necessary for the specific analytical problem at hand. Therefore the tacit presumption that there is an additional amount of material inputs available "at some price" is almost universally made, whenever the traditional marginalist economist is not explicitly considering a problem involving a resource limit.

I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.

Yes,
and I did think about it while writing my comment.

Thinking of efficiency (output/input) in ecological terms, I would say it is fairly easy to estimate by looking at what is not output, that is waste. And our modern societies produce a lot which ends up as waste. Problably a world record in low ecological efficiency. The most ecologically efficient human societies would be those that has little or no waste, that is the societies we see as backwards and poor.

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