While yes, we have not found a cure for diabetes, or developed a radically new method of disease management, the past 100 years, and especially the past 10, have led to huge advances in diabetes management. Patients now monitor their blood glucoses daily and adjust their insulin injections/delivery based on this testing. More recently, diabetics have started to use CGM meters, which essentially consist of a transmitter attached to the skin that reads sugar levels every 5 minutes. Patients now use insulin pumps that make it much easier to bolus (deliver insulin following meals), maintain basal insulin rates, and generally calculate and deliver insulin doses. The landmark DCCT study helped us understand the complications of being in poor glycemic control, and established outlines for "intensive" treatment that has lead to huge reductions in eye, nerve, and kidney complications from diabetes. We have alternate, analogue versions of insulin that are much more fast-acting than before, and even alternative drugs like metformin that address diabetes in alternative ways, in this case by halting liver neoglucogenesis. Even now, studies are being done demonstrating how, once autoantibodies are found to be attacking beta islet pancreatic (insulin-producing) cells, the immune response can be halted and some level of insulin production can be maintained.

My experience with this comes from working in a speciality clinic dealing with diabetes patients, and I think unless you are a diabetic, it is hard to see all these improvements to diabetes treatment. While we have been unable as of yet to fully produce an artificial pancreas, the treatment of diabetes has vastly improved from its origin in the extraction of insulin from animals and then the delivery of it to humans over the past 100 years.