I found Gary Taubes book “Good Calories, Bad Calories” to have some interesting perspective on this subject. Following a very low carb diet, I consumed 5,000 calories a day for quite a while without a change in weight.
Surprisingly, it is not all about calories in vs calories out.
And yes, I think that hyperinsulimia drives weight gain, thereby explaining why many newly diagnosed T2s are overweight. Unfortunately, the ADA has declared war on obesity, which as you just noted is a symptom, not a cause of diabetes.