you have clearly not read much about WWI.... the French Army was the second
best prepared army in Europe, second only to the Germans. they had state of the
art technology.
and prior to that... there was this guy named Napoleon
that kicked butt all over Europe for a while ... he was French too
but let me clarify: no army at that time had incorporated the internal combustion
engine, not the Germans, not the British, not the Austrians. nobody had.
the only Army that thought of using cars was the French, and they had to improvise
and requisition taxi cabs.
clearly, the internal combustion engine was not a military development later used
for civilian purposes, but the other way around.
you are framing the problem wrong. i would suggest you read John Keegan's
A History of Warfare, and Jared M. Diamond's
Guns Germs and Steel: The Fates of Human Societies.