I was playing on the 2nd to most difficult setting. And I understand where you are coming from saying that it is part of the game. It was my fault for not preparing for such a scenario. I had to start over, which was kind of disappointing but not too big of a deal for me.
However, it might be a big deal to others. Especially if they follow the building sequence of objectives that are laid out (as I was) to then be powerless (literally) to do anything for the colony and need to start over. But the simple insertion of the objective to build a backup power source some time prior to a planned lightning strike on the generator would be a great way to challenge the player to prioritize the repair of the generator before that backup power runs out. =)