The problem with your simple model of carbs, fats, proteins is that in people with type 2 diabetes their dietary fats have clogged up their muscle cells ability

The problem with your simple model of carbs, fats, proteins is that in people with type 2 diabetes their dietary fats have clogged up their muscle cells ability to store blood sugars as glycogen. So while removing the "rocket fuel" from the diet its not clear that the underlying problem has been solved. At least not until the fats have been removed from the muscle cells. And yes, transitioning off of a keto diet may lead to the reversal of the positive gains (insulin sensitivity, body composition, average blood sugar level measured using red blood cell oxidation or A1C). And agreed, controversy gains attention which may lead to book sales.