alt Hacker NewsSounds like an argument over semantics and the meaning of the word "breakthrough".
Running the 4 minute mile, climbing everest - those are achievements rather than breakthroughs.
I'd also class the atomic bomb as an achievement - it was the expected/desired result of a massive investment program - though no doubt there were many breakthroughs required in order to achieve that result.
Yup, it's semantics, because the comment I answered stresses "by definition." My point is partly that that isn't the definition.
Even if we decide that breakthroughs require some kind of discontinuity, break, or, as the comment said, "paradigm shift," such discontinuity isn't necessarily "against the grain," as this would imply some kind of resistance to or rejection of "the grain."