Perhaps in the narrow definition of "trenches" your first statement is true. However, a ".. war of maneuver from start to finish ..." is certainly not true. I suspect the combatants in the house to house fighting in places like Stalingrad and Leningrad, did not consider that as "maneuver". Nor did the Americans & Japanese soldiers at Okinawa.

Certainly there was much more maneuver in WWII - blitzkreig - but it lasted a long time and armies were not in constant motion all that time.