Comment by owenversteeg

I think the strongest example by far is nuclear power. We could have used it for everything from energy to warfare to transport to space exploration, and instead we limited our use because the societal costs were too high. Unlike the other examples people cited here, there often isn't a better alternative or a technical reason not to use it. In 2026 nukes are still the best way to destroy your enemies or travel at any appreciable fraction of C or power a ship and the reason we don't do those things is purely societal.