The actual "elephant in the room"... is there is NO such thing as sustainability. Few species have great longevity on this planet... and it is unlikely that ours will be an exception. Species come... species go... the planet did just fine before humans... and the planet will be fine after humans are gone.

Meanwhile.... even solar systems have life spans. If I remember (Jr. High Science class) correctly.... our star (The Sun) will expand and incinerate every planet in the system before it collapses into a Red Dwarf (in 1-3 billion years).

The ONLY chance for your (everyone's) descendants to survive.... or achieve sustainability.... is to escape our cave man roots and explore the stars. We can't do that with bicycles and solar panels. We need, must, have no choice other than... to plunge forward in our grasp of technology.

However the idea of real progress scares the living crap out of the Luddites. And history has shown them to react violently to new fangled things. So... mankind moves only as quickly as the slowest among us can bare.