And it's a more mature arena; mechanical watchers are I'm sure a better example (Gerry Sussman likes to tinker with them to relax, or at least did that while do

And it's a more mature arena; mechanical watchers are I'm sure a better example (Gerry Sussman likes to tinker with them to relax, or at least did that while doing his Ph.D. thesis to stay (semi-)sane), but in the area I know best, everything came together for high power rifles in the 1898 Mauser (although reliably getting the steel right took longer world-wide for the first world). Or look at internal combustion engines. The two absolutely critical technology improvements that changed things from WWI to WWII were "merely" refinements in those and radios. WWI IC engines were so rough they pretty much required wooden frames, and engine power was anemic, as WWI tanks show. Fast forward not very many years and we have much smoother and reliable powerful engines, and had developed the seeds of today's jet engines before the first transistor was demonstrated in 1947.