Maybe it's worth noting that the only time Genesis was used on a planet, it was Regula, which had a massive cave teeming with lifeforms. If there really couldn't be "so much as a microbe", clearly Regula was a poor test subject.
...Unless the cave, kilometers below the surface, was hermetically sealed from the surface, which is pretty likely. If Regula is
Genesis, then we have no evidence that the Genesis effect would do any real rearranging of planetary crust, let alone reach deep below the surface of a targeted planetary body.
Given the secrecy of the project, it could be that Genesis died there and then.
OTOH, given the massive publicity of the project, it would be difficult to keep it from getting reanimated at some point...