Why is fermentation wasteful?

The energy produced by the glycolysis phase is wasted on the fermentation process because if oxygen were present, the pyruvate could go on to the Krebs cycle and the ETS to produce more energy, whereas without oxygen, only 2 ATP result instead of 38. The energy produced by the glycolysis phase is wasted on the fermentation process because if oxygen were present, the pyruvate could go on to the Krebs cycle and the ETS to produce more energy, whereas without oxygen, only 2 ATP result instead of 38.