aa, well asking and expecting are certainly different things 
On your point, it seems to me that a significant number of folks are starting to look at the world the newer way you seem to imply.
For eons this big rock was really really big, too big to move, too big to effect ... so play we do/did.
Many (certainly not all) but many are now looking at the rock as a closed system (at least in a conceptual sense) with only energy input (the sun) but otherwise for the most part a closed system. That is all fine and dandy, but many are also realizing that the 7 or 8 ot 9 billion of us is a lot of us. I don't know what the average is, but if one just says that the average of us is 50kg of moving breathing stuff then that is 400 billion kilograms of moving, breathing, consuming - massively consuming -, stuff.
The last 100+ years in the sandbox has been a simple matter of leveraging a couple hundred million years of chemically stored solar energy in the form of fossil fuels.
Obviously, the math at some point fails (rather quickly). If we require a historical 100 million years of stored solar energy in the form of fossil fuels for every 100 years at our current usage rates, well it pretty obvious, trying to pull this off for a millennium requires a billion years of harvestable fixed carbon. No amount of new extraction technology (shale, sand etc) changes the underlying metric, our consumption dwarfs deposition.
I am of the ecotopia sort ... just everybody chill out, pay more attention to their families, write poems, make music, enjoy sex, and figure out how the universe works (and, of course, travel to other star systems).
The underpinning word is as you mentioned, sustainability.
The sun does continue to beat down, plants continue to fix carbon, and we are adept at harvesting that (as food and fuel). Similarly we are fully capable of transforming the primary plant storage fixed carbon stores into fancy thing equatable with the thingy's of the petrochemical sort.
We are fully versed in biological conversion of sun and dirt into alkanes (e.g. fuel) esters (e.g. clothes, packaging), ketones (e.g. solvents), mono and polycylcic aromatics (e.g. pesticides, antibiotics), and of course food. We can make bullet proof glass out of corn cobs, build AND fuel supersonic aircraft out of twigs and weeds ... it is all there.
The mystery is the amounts we can make per time and the underpinning economics. Big puddles of fossil fuels has for some time been pretty darn cheap, and comparatively, continues to be so.
So, yes, Hope springs eternal. It seems the primary concern is getting over the hump of disturbance consequent to all of this carbon (fossil fuel) waste - climate change, ocean acidification, ...
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