I don’t believe it is a progressive disease at least for me, speaking as a diabetic of 29 years. It is bad habits that are progressive, not the disease. You can always eat what is bad for you and eat too much increasing medications and exercise to compensate but you will get progressively worse. I am highly intolerant of carbs (Need 1 unit of insulin for 3 grams carbs) and have been from first diagnosis in 1990. For years, I increased medications and insulin and exercise to keep A1C between 5.6 and 6.2 while keeping my BMI in the 18-20 range. It worked but I knew there was better to be had.
Recently, after a couple of months of low carb diet (and no exercise) I went from requiring over 50 units of insulin per day to being totally off any medication, including insulin and at age 70 feel 30 years younger. The 2 pieces of hardware I used to make this happen was my digital scale which measures weight in 1/10 of lbs rather than lbs which allowed me to fine tune how much more or less I need to eat to keep my weight up or down to my target and my CGM which shows me through increased and decreased BG levels when I was eating more or less carbs than my body could or could not handle naturally on its own.
I am not on any fancy LCHF, Veggie, Bernstein, Paleo, Atkins, Keto or whatever the latest fad diet is, just cut my carbs to about 20 per day total and then eat as many varied foods as I can according to my CGM and Scale. So yes, it is very possible to get off of all medications even after decades of heavy use.
I now look at my past 30 day Clarity Dexcom results show 100% time in range, with a standard deviation of 15 and am willing to challenge anyone that is not on a low carb diet to come close to that performance. Getting low A1C is not going to help from getting complications if that A1C comes from an average of high, highs and low, lows yet it is the gold standard many people are using to cling to a certain diet.