My take on this is that a reboot is meant to be a temporary change and not a consistent diet that you follow forever. While it is true that you are flooding your body with nutrients during a reboot (and equally important, you are not taking in the toxic crap that most of us used to eat) you are still not getting all of the nutrition that your body needs. You still need protein, and Vitamin B12, and healthy fats and fiber, so a reboot that lasts forever would be harmful after a while. It is meant to be temporary and then followed by a healthy diet and a balanced lifestyle.
My personal history is that I completed my 60-day juice fast and followed it with a balanced diet of healthy food, including a lot of green juice, but also foods like eggs, raw milk, grassfed beef, wild caught fish, lots and lots of fresh & cooked vegetables and even bread (Ezekiel bread) and homemade pasta on occasion. No pizza, burgers, beer, etc...that would put me right back where I started.
I got back into the habit of exercising every day during my reboot, and have kept up that habit, which is a godsend. The more exercise I get, the more I crave green juice. The point I am trying to make is that, like Joe in the hot-air balloon, I committed myself to living a balanced lifestyle and to moving forward. That doesn't make me better or stronger than anyone else (because I am not, trust me) but at least it gives me a daily goal to strive for. I screw up sometimes, so I do a small reboot every once in a while, but overall I'm staying on track.