&gt; People who trust each other can cooperate together without expending resources on protecting themselves.<p>This is not how security works. You need to consider the adversarial case, not the average case.<p>&gt; Consider Bitcoin - the cost of that trustless system that barely works is mind-boggling waste of electricity<p>The &quot;waste&quot; is actually for the purpose of putting a floor on the cost to trick someone into believing a non-consensus history.