[Ibrîniðilpathânezel]

I sometimes suspect that the Elves became more enamored of Art than Invention after Feanor and events of the First Age showed them the seamy underbelly of "progress." Follow it up with the "invention" of the Rings of Power, and one could well decide that Invention is not such a wonderful thing after all; preservation is preferable. Sadly, it also tends to lead to stagnation, because one is always looking back rather than moving forward.

I also think that Sauron didn't go for improving his weaponry because without his Ring, he feared that any devices he might make could be used against him -- just as he feared that his own ultimate weapon, the Ring, might wind up in the hands of some enemy who could use it against him. He appears to have been going for a war of attrition in the Third Age, amassing such huge armies that their sheer numbers would overwhelm the opposition. Fear is also a good ally in such a case, a lesson he bitterly learned when Ar-Pharazon came marching in from Numenor and Sauron's forces (such as they were at that time) took one look and ran. What devices he had available he did use, such as the palantiri in Orthanc and Minas Tirith, but lacking his own master weapon, he probably gained more by sowing distrust and dissent and fear among his enemies. By making them constantly wary of attack, they would need to spend much of their resources in a constant posture of defense, taking the time, manpower, and materiel that might otherwise be used in developing improved technology.