[xereeto]

The transistor was unequivocally the biggest technological breakthrough since fire

[kragen]

breakthroughs since fire more important than the transistor probably include cooking, agriculture, the wheel, metallurgy, glass, ceramics, the heat engine, mechanisms in general (with things like pulleys, hydraulics, screws, and gears), construction cement (originally lime), math, writing, optics, electricity, chemistry (including things like distillation, the atomic theory, and recrystallization), plumbing, carpentry, weaving, sewing, automatic digital computation, and possibly language, depending on when that happened

it seems like maybe you haven't thought much about the history of technology

[anshumankmr]

The mass-energy equivalence and how it led to the discovery of nuclear fission/fusion and how to control/cause explosive atomic chain reactions was probably one of the most impactful technologies of all time, in a literal sense.

[dharmab]

Don't forget: Soap/handwashing, antibiotics, the smallpox vaccine, the Haber-Bosch process, blood transfusion, anesthetic and PCR!