Probably solved in the West decades ago, but that wouldn’t generate the necessary financials for Pharma and the Cult of Medicine.
Actually, you nailed it. I am Type 1 and 20 years ago there was a study using Adult Stem Cells to replace islet cells. I was excited about it because they said it only worked on adult stem cells, embryonic wouldn't take. The cells were transplanted into the liver where for whatever reason were accepted. I waited for another 5 years for trials and testing to finish, only to then hear it "mysteriously" vanished. Always figured it was big phama burying it. Too much money to be made with pills and insulin.
There's another similar study going on now. Being skeptical, I hadn't been following it so don't have a link. As others have mentioned this is a bigger benefit for Type 1 diabetics, who are unable to produce insulin. Some Type 2 diabetics are insulin dependant, but most (at least half) can be cured through proper diet and exercise. I have a half dozen family, friends, and coworkers who have gotten themselves off the pills just by eating better.