Well, the problem with that hypothesis is that the fault that led to the Apollo 13 explosion had nothing at all to do with the LM, lunar landing/surface equipment, or the mission's lunar trajectory. It was a damaged oxygen tank in the SM that exploded. Similar tanks were present in every Apollo spacecraft, both lunar and Earth-orbital. It could have happened on any of the missions.

You're not suggesting that the earlier missions weren't launched at all, are you? Just that they stayed in Earth orbit? (Never mind that it would be impossible to conceal that fact from the many people around the world who were tracking the missions.)