In WWII you did not have enough at several points during the War despite the wide mobilization of manpower resources through out the Empire.
Even the US Army and Marine Corps were seeing the limit on acquiring yet more troops.
What won the war was the combined numbers of Allied Troops and and attrition of Axis Troops as the war progressed.
Troops have to be supplied with the needs to conduct training and combat operations thus logistics is the decider in the outcome of a war.
WEB.....this month's "Proceedings" has yet more useful articles re Submarines and Sub Warfare and specifically addresses Undersea Cables and by extension undersea pipelines.