I don't think we can compare.
The revolutionary war was due to British control of the colonies and the exploitation of the labor of the colonists (among other things).
WW1 was caused by a Serbian nationalist assassinating Franz Ferdinand and the subsequent reply from Serbia of "fuck you" when Austria-Hungary issued an ultimatum.
WW2 was caused as a direct result of WW1. Hitler's rise to power came from the failure of the Weimar Republic and Germany's insolvency in it's reparations because of WW1.
None of those wars were fought as a result of the depressions.