Keto and cardio absolutely work, the problem is that it's the hardest diet to adjust to, thats where most people fail, the adaptation period switching from carbs to ketones is hell, for my prep it took about 2 weeks for my body to transition and I felt like death. I called my coach 3 times and told him I quit, he kept telling me to hang in there and kept upping my fats, zero energy, zero pump, zero intensity. The average gym rat is not going to go through that shit and on top of that try to work a 9-5. If it wasn't for me being in prep, I would've quit that diet in 4 days. However, if you stick to it you will see your physique transform by the day once you hit ketosis, I never seen changes that rapidly, not to mention limitless energy. But you gotta suffer to get into ketosis and not many people are willing to do that.