dohboi wrote:"Is sustainability an illusion?"
Pretty much.
A truly sustainable society would use essentially no mined resources, since those cannot be sustainably 'harvested'--they do not pre-produce themselves on anything like human time scales.
(For metals, we are talking about lifetimes of multiple stars to produce, iirc.)
That also goes for any fossil fuel use.
And the things that are left that you CAN use, have to be use very modestly, harvesting them at well below replacement level.
To my way of thinking if you are not self sufficient you are not sustainable. Darn few of us could build ourselves a bicycle, even an old fashioned wooden one using a rope drive instead of a chain. Maybe you have a big enough piece of land to pasture a horse, but other than that you are on Shank's Mare, that is to say walking under your own power. It gets worse from there, even with permaculture and good luck in the weather/climate you need a lot of food to live until the harvest, and then what you harvest has to last you until the next one after that. Now that you have so much energy tied up in raising your food and maintaining your transportation you have to maintain your house. Without the aid of outside contractors unless you can sell enough surplus food to pay for those kind of specialists.
It gets worse from there, what happens when your wife goes into labor or your four year old is running a high fever?
Our entire western culture is based on everything being cheap because energy was cheap for a hundred years. My great grand parents saved every scrap of food off the table for leftovers or animal feed, how much did you throw away this weekend? My dad had a pail in the basement half full of bent nails that were straitened out and reused when assembling anything out of soft pine or other soft wood. He had another mess of assorted nuts, bolts, screws and washers so that when something on the farm broke you could put together a patch work job to keep the work going. He was 85 when he passed away last September, but he still had that stuff because it was a lifestyle habit. Never throw away today what you might have a use for tomorrow, never buy new when used will do the job.
People in poor countries still live that way, and IMO they will have a much better chance of surviving the post oil transition than the spoiled generation of westerners alive today.