Insulin used to be costly and complicated to manufacture, now it costs $25-35 for vials of standard basic varieties in non-insane countries with proper regulation of the pharmaceutical and medical industries (sorry united States, this doesn't include you). This treatment was almost unimaginable just at the turn of the millennium, but is now reality, affordable therapy shouldn't be impossible although it may take time to lay that groundwork.

I dont see why. Culturing cells back into stem cells is very cheap. Maybe expensive to do in bulk, but you dont need to do it in bulk. You only need maybe a dozen stem cells. The hard part would be modifying the cells to produce insulin. But once you have a retrovirus to do that, that becomes almost free considering its absurdly easy to replicate viruses. After that, youd just have to culture the cells to get more, again, very easy.

I havent read the article yet, but depending on how they reintroduce those cells back into the body is almost certainly the most expensive part excluding down investment on originally creating the virus, which only has to be done once.

Edit: see my comment below

Because we don't have widespread deployment of treatments like this, we still understand next to nothing about the underlying autoimmune disorder that causes the body to attack its own pancreas in the first place - type 1 diabetes is effectively a symptom of something else rather than its own disease. Stem cell derived transplants are normally completely free from rejection risk due to being cells from the patient's own body, but if your immune system destroyed something once, transplanting in something identical to replace it wouldn't be expected to go any better. That means you still need immunosuppressants like you would if you had a transplant from someone else, and those are generally considered riskier than having type 1 diabetes is in the first place. The patient in the study had already had two liver transplants and a failed pancreas transplant, so was already taking the necessary drugs. Offering this treatment to someone who hadn't already had a transplant would probably be pretty unlikely unless their blood sugar control with insulin injections and sensible eating was genuinely awful.

There are other experimental treatments that involve other ways of protecting the insulin-generating cells from the immune system, like membranes that allow insulin and sugar through, but not white blood cells. That's apparently a harder thing to do as that's been in progress since before stem cells were viable. However, once it is working, you can just use off-the-shelf genetically modified bacteria rather than bespoke stem cells, and avoid the need for immunosuppressants, so it should work out as the better treatment eventually.