I wouldn't place too much store in tv dramas hemase. The few examples we see are often innacurate and very ill-informed. It certainly used to be the case that a diagnosis of diabetes would mean a curtailed lifespan, but with modern treatment regimes and medical knowledge of the causes, prevention and treatment of complications life-expectancy has been significantly enhanced.
I was reading a book recently 'Diabetes, the Biography', and it is quite shocking (to me, in the current day) how there was often an 'inevitablity' accepted that diabetics would suffer complications. For this reason, many were 'allowed' to run higher levels as it was thought that this at least would improve the quality of their lives by placing less restriction on diets and lifestyles. This was as recent as the 1970s, and there has been tremendous progress since then. I am sure any of the longer-term diabetics in the forum could tell you how things like accurate blood testing with portable meters is such a huge improvement, for one.
We don't know what lies ahead for any of us, the best we can do is do our best to keep our levels within range and this will gve us the best chance of avoiding complications. Diabetes, unlike many other chronic conditions, is on the whole a manageable condition if we are prepared to put in the work.
Personally, in some ways I believe my life-expectancy has been enhanced by my diagnosis, as I have made lifestyle changes that will lessen the risk of other problems later in life. I would rather not have it, but I do not fear it - at the same time, I am not complacent and know I must not let my guard slip.