Technology was the single biggest factor in WW1 being waged the way it was.
Military strategy had yet to fully understand how to use recent technological advances (particularly, the machinegun, heavy artillery, and the submarine). As a consequence, old strategies turned out to be completely useless (or, worse, massive failures). The manner in which most of the fighting in WW1 occurred reflects military leadership slowly groping about to fully understand how these new technologies worked, and the implications for strategy and tactics. That is, how to effectively use these new weapons, and, on the other side, how to effectively counter their use.
The sad fact is that military leadership on both sides during WW1 was sadly lacking in intelligence and the ability to grasp that these new technologies had radically changed warfare, and that a corresponding whole new paradigm of tactics was required. Their stupidity cost Europeans 4 long years of war, and 10 million deaths.
In 1915, new technology had once again created weapons that were more powerful and deadly than the old ones. For one thing, in April 1915, Germany began using poison gas as a weapon. The gas burned lungs & blinded eyes. Soon, both sides used gases against each other. Germany continued developing deadly gases.
Actually, the aforementioned tanks, airplanes, and chemicals were generally the ONLY