I wonder if working with people with diabetes you become de-sensitised to high numbers and her 10% doesn't seem too bad to her?
High numbers and low expectations I suspect. I think you're right in that they get used to seeing people with high A1cs and unable to get them lower simply because they lack the tools to improve things.
Then there's the belief that T2 is "progressive". Well of course if the BGs are out of control, it is. So 10 years down the line when she has neuropathy, retinopathy and nephropathy she will not be surprised. Trying to tell her that its just not necessary to suffer from any of them is a hard job.