In contrast to modern warfare, rapid technological change really did not happen in antiquity. When technological progress did happen, it tended to occur very slowly, with “game-changing” innovations rare. Not adopting a new technology, such as a Greek double-grip shield or a Roman pilum, did not put a combatant at a severe disadvantage, in the way refusing to use the machine gun might a modern army. A quote from Lendon is illustrative of this idea:

A soldier who went to sleep in his war gear in the fifth century B.C. would have been able to fight at no disadvantage in that equipment if he awoke in the fourth century A.D., eight hundred years later. Imagine, by contrast, how confused- and how dead- a knight of 1200 A.D. would be if he blundered into a contemporary battle (Lendon 8)

Technological progress thus did not really drive changes in ancient warfare the way it does today. New technologies were created, but at a comparatively far slower pace, and few were particularly radical. Therefore, changes in military technology really didn’t change the tools of life available to the inhabitants of the Roman world, or significantly alter aspects of ancient life.

The best examination of change in Greco-Roman warfare is J.E. Lendon’s Soldiers and Ghosts: A History of Battle in Classical Antiquity, from whose introduction I’ve paraphrased much of this response. Since technological change was slow, Lendon argues that cultural shifts, predominantly innovation that attempted to recreate the past, drove changes in Greek and Roman warfare. I would however caution against this book as an introduction to the topic of ancient warfare. Lendon seeks to answer different questions than a more traditional text, and his conclusions, while largely sound (though I disagree with a significant portion of his Roman section) are a bit novel.