|Quoting planemaker (Reply 148):|
“The Stone Age did not end for lack of stone, [...]
Actually most - if not all - "Ages" [civilicatory supercycles] ended with a widespread collapse [for whatever reason], which comes with desintegration, complexity-reduction, "localisation", population decline, vanishing of knowledge, vansihing of "international" trade, almost always massive decline of cultural centers [= big cities], vanishing of the elites etc. etc.
Eventually - after some time - new "societies/civilisations" emerged which indeed where typically based on fundamental new knowledge, culture and technologies like bronze, writings, iron, coal + steam engine, ...
That's not to say that every substitude comes with a society collapse - e.g. oil substituting coal [while the use of coal still rising anyway] - but that it's not a "given" things will play out that way. Typical any "substidude" in one civilisation cycle comes with a higher complexity level - all systems getting more-and-more complex and interlinked and come with a tendancy towards "monopolization" - until these systems get more-and-more fragil and finally falling apart [triggerd by external factors like war/civil war, environmental change or brakeup of long-range trade] in cascading failures.
Odds are very high our cycle will "end" with large-scale-blackouts because if someone "pulles the plug" it's over within a week or two.