From the article I posted in #15:
But the argument that life seems to have evolved very early and quickly, so therefore is inherently likely, can be turned around, Dr. Joyce said. “You could ask why, if life were such a probable event, we don’t have evidence of multiple origins,” he said.
In fact, with trivial variations, there is only one genetic code for all known forms of life, pointing to a single origin.
Maybe the Bombardment was the “historic accident”than gave us us essentially one genetic code.