Those seem like fine partial explanations to me, as do the explanations I listed in the OP. I expect multiple things went right simultaneously; if it were just a single simple tweak, we would expect many other groups to have hit on the same trick.
Those seem like fine partial explanations to me, as do the explanations I listed in the OP. I expect multiple things went right simultaneously; if it were just a single simple tweak, we would expect many other groups to have hit on the same trick.