We've historically often engaged in unsustainable practices, like:

1. hunting whales for lamp oil

2. cutting down trees for fuel to make glass and build ships

3. using natural rubber

4. no sanitation in the cities

5. using horses for transportation

6. using well water in cities

As these became unsustainable, alternatives were discovered and developed.

Historically we engaged in major conflict between equal powers, such as the two World Wars. Then... nukes. Tech doesn’t always magically resolve itself, sometimes it’s just an apocalypse in waiting.

Or in some cases they weren’t, and civilizations collapsed.

To support your point: https://en.wikipedia.org/wiki/Societal_collapse#Theories

I'd say rather that as alternatives were discovered and developed, these became unprofitable.

Increasing unsustainability leads to price increases, which encourages the development of cheaper alternatives, and then they become unprofitable.

The development of synthetic rubber was a direct result of high prices and inability to increase natural rubber production.

Not sure if any of your examples actually shows unsustainability leading to price increases.

Whale hunting stopped when synthetic oils became available and cheaper than "natural" ones. I think the natural ones were still cheap enough.

Coal, and later oil, was a better (-> cheaper) fuel than trees, so people switched. Shipbuilding materials changed as new fuels and new weapons became available. We're not running out of trees, the alternatives were just better.

Sanitation AFAIK was purely a result of scientific discoveries finally being accepted by practitioners, and then by masses.

Horses were definitely useful and cheap enough for transportation - internal combustion engine created a cheaper/better alternative.

I won't comment on natural rubber and wells in cities, because I don't know anything about it.

My point is - at least with some of your examples, there was no strong price increase signal, and thus we can't use them to support the idea that market pressures will always occur right in time to save us.

The original reason for the Jamestown colony, for example, was the high price of wood fuel for making glass. Nobody would have funded such an expensive expedition for making glass otherwise.

Whaling originally was plentiful right off the coast of Massachusetts. These were depleted, and whalers had to go steadily farther out, then into the Pacific, then to the edges of the Pacific. These voyages got longer and longer, and more and more dangerous, and so price increases would have accompanied them.

http://www.petroleumhistory.org/OilHistory/pages/Whale/price...

> cheap enough

It's a tautology that people will use something that is "cheap enough" until there are cheaper alternatives.

> Increasing unsustainability leads to price increases

Not if there is nobody alive anymore to raise prices. This theory works well for progressive change but doesn't hold for long-term brutal changes, e.g. maybe historically if people dried the only well in their village there was no price increase (or there was an instantaneous price increase to infinity if you prefer) because the village was doomed.

Soil depletion is not going to be an abrupt change.